Reference

Terms and Definitions

Plain-language definitions of the terms used across THR research, grouped by subject. Choose a category, or filter the whole list.

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3D NAND (vertical NAND, V-NAND, layer count)Computing: NAND flash built by stacking hundreds of layers of memory cells vertically. Adding layers raises density without shrinking cells.
3GPP (3rd Generation Partnership Project)Aerospace: The partnership of standards bodies that writes the technical specifications for mobile networks such as 4G LTE and 5G, issued in numbered releases.
4E basis (4E)Industry: A reporting basis for platinum-group metal output that counts platinum, palladium, rhodium and gold together.
10 CFR Part 53 (Part 53)Industry: The NRC's risk-informed, technology-inclusive licensing rule for advanced reactors, finalized in 2026. It is an optional path alongside the older Parts 50 and 52.
14 CFR (Title 14 of the Code of Federal Regulations, Federal Aviation Regulations)Aerospace: Title 14 of the US Code of Federal Regulations, which holds the federal rules on aviation and commercial space. Its parts are cited by number, such as Part 107 for small drones.
45ZCF-GREETSustainability: The version of the GREET model published by the U.S. Department of Energy and Treasury specifically to calculate carbon intensities for the Section 45Z credit.

A

AACE cost estimate classes (Class 4 estimate, Class 3 estimate, AACE 18R-97, AACE)Minerals: The AACE International scale that grades capital cost estimates from Class 5 (concept, least accurate) to Class 1 (definitive). Accuracy bands narrow as engineering advances.
Abyssal plain (abyssal, abyssal zone)Minerals: The flat, deep ocean floor, mostly 3,000–6,000 m down, where polymetallic nodules lie.
Accelerated depreciationFinance: Depreciation methods that expense more of an asset's cost in its early years and less later. They lower taxable income sooner without changing the total amount deducted over the asset's life.
Accelerating rate calorimetry (ARC, heat-wait-seek)Batteries: A safety test that heats a cell in steps, waits and watches for self-heating, a method called heat-wait-seek. It reveals the temperature at which the cell begins to run away.
Accounting creditSustainability: A deduction from a product's reported emissions that comes from a rule or a claimed benefit rather than from a physical cut in the supply chain. Examples include credits for co-products, soil-carbon gains or avoided waste.
Accretion / dilutionFinance: An analysis of whether a deal raises (accretive) or lowers (dilutive) the acquirer's earnings per share. Dilution also describes existing shareholders owning a smaller percentage after new shares are issued.
Actinic inspectionComputing: Inspecting EUV masks with light of the same 13.5 nm wavelength used to print, which reveals defects other light cannot.
Active material (electrode active material)Batteries: The material in an electrode that actually stores and releases charge, as opposed to binders, conductive additives and foils. Cathode active material is usually the most expensive part of a lithium-ion cell.
Active tail hedgingFinance: Protection against large market declines that is adjusted over time, for example by buying, rolling or selling options as prices and volatility change. The aim is to manage the ongoing cost of protection rather than holding a fixed hedge.
Actual lossFinance: A loss that has been realized by selling below cost, or a current value below the principal invested. It differs from a drawdown, which measures a fall from a peak that may still be above cost.
Adaptive Acquisition FrameworkAerospace: The set of acquisition pathways the US Defense Department uses, from urgent needs and middle-tier rapid programs to major weapon systems and software, each with its own rules.
Additional secondary factor (ASF)Maritime: The extra delay a Loran signal picks up crossing land of varying conductivity. It must be mapped and corrected for accurate positioning.
AdditionalitySustainability: The test of whether a claimed benefit would have happened anyway. A feedstock, credit or project is additional only if the fuel demand actually caused it.
Additive manufacturing (AM, 3D printing, 3D-printed)Industry: Building parts layer by layer from a digital model, instead of cutting them from solid stock. It allows complex shapes and part consolidation but is slower and costlier per part than mass production.
Advanced air mobility (AAM)Aerospace: A broad term for new air transport using electric or hybrid aircraft, often with vertical lift, for passengers and cargo over short and regional distances. It includes air taxis, regional routes and drone delivery.
Advanced packaging (heterogeneous integration, 2.5D packaging, 3D packaging)Computing: Methods for connecting chips densely inside one package, such as interposers, 2.5D and 3D stacking and hybrid bonding. It has become a main lever for AI chip performance alongside transistor scaling.
Advisory circularAerospace: FAA guidance that describes acceptable, usually voluntary, ways to meet a regulation.
Affordable massAerospace: A defense strategy of fielding large numbers of cheaper, often uncrewed, systems instead of a few expensive ones, to overwhelm defenses and absorb losses.
AFRL (Air Force Research Laboratory)Aerospace: The research laboratory of the US Air Force and Space Force, covering aerospace vehicles, propulsion, materials, sensors and directed energy.
Aggregation problemFinance: The difficulty of combining many different items or behaviours into one meaningful total, such as adding unlike machines into a single figure for capital or treating a market as one average buyer. Aggregate figures can hide the variation that actually drives outcomes.
AI accelerator (accelerator, custom silicon)Computing: A chip designed specifically to run AI workloads faster or more efficiently than general-purpose processors, such as GPUs, TPUs and NPUs.
AI agent (agentic AI, AI agents)Computing: An AI system that plans and carries out multi-step tasks by calling tools, software or other services, instead of only answering a single prompt.
Air operator certificate (AOC, air carrier certificate)Aerospace: Approval for a company to carry passengers or cargo commercially, covering its procedures, crews and maintenance.
Air separation unit (ASU, cryogenic air separation)Industry: A plant that cools air until it liquefies and separates it into oxygen, nitrogen and argon by distillation.
Air-breathing propulsion (air-breathing)Aerospace: Engines that take oxygen from the surrounding air instead of carrying it, such as jet engines, ramjets and scramjets. Not carrying oxidizer raises efficiency but limits them to the atmosphere.
AirworthinessAerospace: The condition of an aircraft that conforms to its approved design and is safe to operate. Regulators grant it through type, production and individual airworthiness certificates.
Airworthiness certificate (standard airworthiness certificate)Aerospace: Approval that an individual aircraft conforms to its type design and is safe to fly. Each aircraft carries its own.
Alkaline intrusion (alkaline complex, peralkaline intrusion, peralkaline complex)Minerals: A body of igneous rock unusually rich in sodium and potassium. Peralkaline intrusions can concentrate rare earths, zirconium and niobium, often with uranium and thorium.
Allam cycle (Allam-Fetvedt cycle, oxy-combustion cycle)Industry: A power cycle that burns natural gas with pure oxygen in supercritical CO₂, producing pipeline-ready CO₂ and almost no other emissions.
Allan deviation (Allan variance)Maritime: A measure of how stable a clock or sensor is over different averaging times, used to compare gyroscopes, accelerometers and oscillators.
Allocation (co-product allocation)Sustainability: Splitting the emissions of a shared process among the products that come out of it. Crushing soybeans yields both oil and meal, so the farm's emissions must be divided between them. The splitting rule can move a result by more than 10 g CO₂e/MJ.
Allocation hierarchySustainability: The order of preference ISO 14044 sets for handling co-products: first avoid allocation by subdividing processes or expanding the system, then allocate by physical relationships, and only then by economic value. No regulatory framework follows this hierarchy strictly.
AlNiCo magnet (AlNiCo, Alnico)Minerals: An aluminum-nickel-cobalt magnet with excellent heat stability but low coercivity, used in sensors and instruments.
AlphaFinance: Return in excess of what exposure to the market, or to a stated set of factors, would explain. Alpha is a residual: it depends entirely on which factors were included in the model.
Alumina (aluminum oxide, Al₂O₃)Industry: Aluminum oxide (Al₂O₃), the white powder refined from bauxite that is fed to aluminum smelters. About 2 t of alumina make 1 t of aluminum.
Ambient noise (ocean ambient noise)Maritime: Background sound in the sea from waves, rain, shipping and marine life, against which a sonar must detect targets.
America MakesIndustry: The US national additive manufacturing innovation institute, part of the Manufacturing USA network, which funds shared research with industry and government.
American Security Drone ActAerospace: A US law, enacted in the 2024 National Defense Authorization Act, on drones from covered foreign entities, chiefly Chinese manufacturers. It bars federal agencies and federally funded projects from buying or operating them. Its federal-funds restrictions took effect in December 2025.
Ammonia: grey, blue and greenSustainability: Ammonia (NH₃) is the base of nearly all synthetic nitrogen fertilizer, made by combining hydrogen with nitrogen from the air in the Haber-Bosch process. The color follows the hydrogen: grey ammonia uses hydrogen from unabated natural gas; blue ammonia captures and stores the CO₂ from that step; green ammonia uses hydrogen from electrolysis on renewable power.
Ammonium nitrate (calcium ammonium nitrate)Industry: A nitrogen fertilizer, also used in mining explosives. It can detonate if contaminated or heated in bulk, so storage is tightly regulated.
Ammonium paratungstate (APT)Minerals: The main refined tungsten chemical and the industry's price benchmark, made by dissolving concentrate and crystallizing it. It is reduced to oxide and metal powder.
Ammonium perchlorateAerospace: The standard oxidizer in solid rocket propellant, mixed with aluminum powder and a rubbery binder. Few plants make it, so its supply limits how fast missile and motor production can grow.
AmortizationFinance: Spreading the cost of an intangible asset, such as a patent or software licence, over its useful life. The word also describes repaying a loan through scheduled payments of interest and principal.
Amortization periodSustainability: The number of years over which a one-off land-use emission is spread when it is converted into a per-megajoule figure. A longer period makes the same emission look smaller per year. GLOBIOM's palm value is 231 g CO₂e/MJ over 20 years, 185 g over CORSIA's 25 years and about 154 g over 30 years.
Ampere-hour (Ah, amp-hour, mAh)Batteries: A unit of electric charge: one ampere flowing for one hour. Cell capacity is given in ampere-hours; multiplying by voltage gives energy in watt-hours.
Analog computing (analog compute-in-memory)Computing: Computing with continuously varying signals, such as currents or light intensities, instead of digital bits. It can be efficient for matrix math but is limited by noise and precision.
Ancillary services (grid services)Batteries: Grid support services beyond selling energy, such as frequency regulation, reserves and voltage support. They are often the first profitable market for new storage.
Animal by-product categories 1, 2 and 3Sustainability: The EU's risk classes for animal material not intended for human consumption, set by Regulation (EC) No 1069/2009. Category 1 is the highest risk, such as material linked to transmissible spongiform encephalopathies; Category 2 includes fallen stock and manure; Category 3 is low-risk material from healthy animals. Categories 1 and 2 are barred from feed and mostly burned for energy, so using them displaces little; Category 3 fats compete in feed, pet food and oleochemicals, and palm is their likely substitute.
Annex IX Part BSustainability: The list in the EU RED of feedstocks, principally used cooking oil and animal fats, whose contribution to transport targets is capped because supply is limited. The cap is 1.7 percent of transport energy; Germany has raised it to 1.9 percent.
Annex V and Annex VIIISustainability: Annex V of the EU RED sets the calculation rules, the 94 g fossil comparator and the typical and default values for biofuels. Annex VIII sets provisional ILUC estimates, 55 g CO₂e/MJ for oil crops, which are reported but not counted toward compliance.
Anode (negative electrode)Batteries: The negative electrode of a battery during discharge, where the stored material gives up electrons. Graphite is the standard anode in lithium-ion cells; silicon, lithium metal and hard carbon are alternatives.
Anode effectIndustry: A disturbance in an aluminum cell, when alumina runs low, that sharply raises voltage and releases perfluorocarbon gases.
Anode slimes (anode slime, anode mud)Minerals: The insoluble residue that collects under anodes during copper electrorefining, a source of gold, silver, tellurium and selenium.
Anode-free cell (anode-less)Batteries: A cell built with no anode material: lithium from the cathode plates directly onto the copper foil on first charge. It saves weight and cost but makes cycle life even harder to achieve.
Anomaly detectionComputing: Automatically flagging data points or patterns that differ from normal, such as a leak, intrusion or failing machine.
Anorthosite (anorthite, plagioclase, plagioclase feldspar, ferroan anorthosite)Minerals: A pale rock made mostly of plagioclase feldspar that forms the lunar highlands. Its calcium-rich form, anorthite (CaAl₂Si₂O₈), is the Moon's main aluminum source.
Antenna gain (gain)Aerospace: How strongly an antenna concentrates radiated power in a given direction, compared with a reference antenna, in decibels.
Anti-dumping investigationSustainability: A trade inquiry into whether imports are sold below fair value, which can end in extra import duties.
Anti-submarine warfare (ASW)Maritime: Finding, tracking and attacking enemy submarines, mainly with sonar from ships, aircraft, submarines and sonobuoys.
Antidumping and countervailing duties (antidumping duty, anti-dumping duty, countervailing duty, AD/CVD)Industry: Extra import duties that offset goods sold below fair value (antidumping) or supported by foreign subsidies (countervailing). They are set product by product after investigations.
Antifouling coating (antifouling, anti-fouling paint)Maritime: Hull paint that stops barnacles, weed and slime from attaching, cutting drag and fuel use.
Antimony (antimony metal, antimony ingot, antimonial lead)Minerals: A brittle metalloid used mainly as a flame-retardant additive, in lead-acid batteries, glass and ammunition primers. Metal is traded at ≥99.65% purity.
Antimony trioxide (Sb₂O₃)Industry: The main industrial antimony compound, used chiefly with halogenated chemicals as a flame-retardant booster in plastics and textiles, and as a catalyst for PET plastic.
API (application programming interface, APIs)Computing: Application programming interface: a defined way for one piece of software to request data or services from another. AI models and cloud services are sold largely through APIs.
Apparent consumptionMinerals: Production plus imports minus exports, adjusted for stock changes, used to estimate a country's use of a material.
Approximate nearest neighbor search (ANN, ANN search, approximate nearest-neighbor)Computing: Finding the stored vectors closest to a query quickly by accepting a small chance of missing the exact best match. It makes large-scale vector search practical.
Aquaculture (fish farming, mariculture)Maritime: Farming fish, shellfish and seaweed in controlled conditions, on land or in open water. Since 2022 it has produced more aquatic animals than wild capture fisheries.
Aquaculture Stewardship Council (ASC, ASC certification)Maritime: An independent body that certifies responsibly farmed seafood against environmental and social standards.
AquaponicsMaritime: A combined system in which fish waste fertilizes plants grown in water, and the plants clean the water for the fish.
AR6Sustainability: The Intergovernmental Panel on Climate Change's Sixth Assessment Report, completed in 2021 to 2023. It updated the warming factors used to convert methane and nitrous oxide into CO₂e: 27 for biogenic methane and 273 for N₂O over 100 years. The EU RED still uses the older values of 25 and 298.
Areas of Particular Environmental Interest (APEI, APEIs)Minerals: Zones the International Seabed Authority sets aside from mining in the Clarion-Clipperton Zone to protect representative seabed habitat.
Argonne National LaboratorySustainability: A U.S. Department of Energy research laboratory near Chicago that develops and maintains the GREET and CCLUB models.
ARP4761 (SAE ARP4761)Aerospace: An SAE guideline for safety assessment of civil aircraft systems, using methods such as fault tree analysis to show that failure probabilities meet their targets.
Artemis AccordsAerospace: Non-binding principles for civil space exploration, led by the US, covering transparency, interoperability, sharing of scientific data and avoiding harmful interference. Countries join by signing.
Artemis program (Artemis)Aerospace: NASA's program to return astronauts to the Moon and build a sustained presence there, with commercial and international partners. Its missions are numbered, as in Artemis II and Artemis III.
Artisanal and small-scale mining (ASM, artisanal mining)Minerals: Informal, mostly manual mining by individuals and small groups. It supplies much of the world's tantalum and some cobalt and gold, with high safety and traceability risks.
AS9100Aerospace: The aerospace and defense quality management standard, built on ISO 9001 with added requirements. Most aerospace buyers require suppliers to be certified to it.
ASIC (application-specific integrated circuit, ASICs)Computing: Application-specific integrated circuit, a chip designed for one task. It beats general processors on speed and energy for that task, as bitcoin miners and AI accelerators show, but cannot be repurposed.
Assay (assays, fire assay)Minerals: A laboratory analysis that measures the metal content of a rock, concentrate or product sample.
Assessed price (price assessment, price reporting agency, Fastmarkets, Argus, Shanghai Metals Market, SMM)Minerals: A price set by a price reporting agency from surveyed trades and offers, used for metals without liquid exchange futures, such as tungsten, antimony and rare earths.
Assured access to spaceAerospace: The US policy goal of keeping at least two independent launch vehicles able to carry national security payloads, so one failure does not ground them all.
Asteroid spectral types (C-type asteroid, S-type asteroid, M-type asteroid, C-type, S-type, M-type)Minerals: Classes of asteroid by surface composition: C-type are carbon-rich and may hold water; S-type are stony; M-type appear metallic, rich in iron, nickel and possibly platinum group metals.
ATEX (ATEX directive)Computing: The EU rules for equipment and workplaces in explosive atmospheres. Sensors used in such areas must be certified to them.
Atom interferometry (atom interferometer, cold-atom interferometry, matter-wave interferometry)Maritime: Measuring acceleration or rotation by splitting a cloud of laser-cooled atoms into matter waves and recombining them; the interference pattern reveals motion with very low drift.
Atomic clock (chip-scale atomic clock, CSAC, optical clock, optical atomic clock)Maritime: A clock that keeps time from the steady frequency of atomic transitions. Chip-scale versions let vehicles hold accurate time without satellites; optical clocks are more precise still.
Attributional accounting (attributional LCA)Sustainability: A way of measuring emissions that divides up the pollution of an existing supply chain among its products, as a snapshot. It asks: what share of today's emissions belongs to this fuel? It ignores the knock-on effects of extra demand. The EU RED, CORSIA core values and GREET direct results are attributional, and they assign wastes zero upstream burden.
Attritable (attritable aircraft, attritable systems)Aerospace: Cheap enough that losing some in combat is acceptable, yet designed to be reused if they survive. Attritable aircraft sit between expendable munitions and costly crewed jets.
AUKUS Pillar II (AUKUS, Pillar II, Pillar 2, AUKUS Pillar 2)Maritime: The advanced-capabilities track of the Australia-UK-US security pact, covering undersea autonomy, quantum technologies, AI and hypersonics. Pillar I covers nuclear-powered submarines for Australia.
Autocatalyst (catalytic converter, three-way catalyst, diesel oxidation catalyst)Industry: A catalytic converter in vehicle exhaust that uses platinum-group metals to turn pollutants into less harmful gases. Three-way catalysts treat gasoline exhaust; oxidation catalysts treat diesel exhaust.
Autonomous mobile robot (AMR, automated guided vehicle, AGV, AGVs)Industry: A wheeled robot that navigates a factory or warehouse on its own using sensors and maps. Automated guided vehicles do the same along fixed routes marked by wires, tape or beacons.
Autonomous underwater vehicle (AUV, AUVs)Maritime: An untethered robot submarine that runs a mission on its own, without continuous human control, surfacing or using acoustic links to report.
AutorotationAerospace: A helicopter's ability to descend safely without engine power, with upward airflow keeping the rotor spinning so it can cushion the landing. Many eVTOLs cannot autorotate and rely on redundancy instead.
Auxiliary engine (auxiliary generator, genset)Maritime: A ship's smaller engine-generator set that supplies onboard electricity, separate from the main propulsion engine. It often runs in port unless shore power is used.
Average true range (ATR)Finance: The average, over a stated window, of each day's true range: the largest of the high-low range, the high minus the prior close, and the prior close minus the low.
Avoided-emissions creditSustainability: A credit claimed because using a material prevents emissions that would otherwise occur, for example waste oil that would have rotted and released methane.

B

Back end of line (BEOL, front end of line, FEOL)Computing: The later chip-making steps that build the layers of metal wiring connecting transistors. Front end of line builds the transistors themselves.
BacktestFinance: A simulation of how a rule-based strategy would have performed on historical data. Backtests systematically overstate results unless survivorship, look-ahead, and costs are handled.
Backward and forward integration (backward integration, forward integration)Industry: Backward integration takes over supply steps, such as a carmaker making its own batteries. Forward integration takes over steps toward the customer, such as a miner making finished magnets.
Balance sheetFinance: A statement of what a company owns (assets), what it owes (liabilities) and the owners' residual interest (equity) at a single date. Assets always equal liabilities plus equity.
Ballast (ballast water, ballast tanks)Maritime: Water or other weight carried low in a ship to keep it stable and trimmed when it is lightly loaded.
Ballistic coefficientAerospace: A measure of how well a falling body pushes through drag: its mass divided by its drag coefficient times frontal area. A low value means the vehicle slows high in the atmosphere, where heating is gentler.
Ballistic recovery parachute (whole-airframe parachute, ballistic parachute)Aerospace: A parachute deployed by a small rocket that lowers an entire aircraft to the ground in an emergency. It is common on light aircraft and some eVTOL designs.
Barrels per day (bpd, b/d, bbl/d, bbl)Industry: The standard unit of refinery capacity and oil production. One barrel is ≈159 litres.
Baseload and dispatchable power (baseload, dispatchable, firm power)Industry: Baseload power runs steadily around the clock; dispatchable power can be turned up or down when needed. Both are prized against weather-dependent wind and solar.
Basis pointFinance: One hundredth of one percent. 25 basis points is 0.25%.
Basket price (PGM basket, basket price per ounce)Minerals: The combined value of all metals a mine produces per unit of output, such as per 4E ounce for platinum group metal mines.
Bathymetry (bathymetric survey, seafloor mapping)Maritime: The measurement and mapping of water depth and seafloor shape, mainly with ship-mounted multibeam sonar.
BatteryBatteries: A device that stores energy chemically and releases it as electricity, built from one or more electrochemical cells. In industry use, the word often means a whole pack or storage system.
Battery categories (EU) (portable battery, LMT battery, light means of transport battery, industrial battery, EV battery)Batteries: The EU Battery Regulation sorts batteries into five types, each with its own rules. See the table
Battery energy storage system (BESS, battery storage, grid battery)Batteries: A stationary installation of batteries, inverters, controls and safety equipment that stores electricity for later use. Most new grid-scale systems use LFP cells in shipping-container units.
Battery management system (BMS)Batteries: The electronics and software that monitor a battery's cells and keep them within safe limits. It estimates state of charge and health, balances cells and controls charging.
Battery module (module)Batteries: A group of cells wired together in a frame with sensors and connections, which in turn is assembled into a pack. Many newer packs skip modules altogether.
Battery pack (pack)Batteries: The complete battery as installed in a vehicle or product: cells or modules plus housing, cooling, wiring and a battery management system. Pack-level energy density is always lower than cell-level.
Battery passport (digital battery passport)Batteries: A digital record, linked by QR code, of a battery's origin, materials, carbon footprint and condition. The EU requires one for EV, light-transport and large industrial batteries from 18 February 2027.
Battery swapping (battery swap)Batteries: Replacing a vehicle's depleted battery with a charged one at a station, instead of charging it in place. It takes minutes but needs standardized packs and costly station networks.
Battery-grade (battery grade)Batteries: Material refined to the very high purity cell makers require, such as nickel sulfate, cobalt sulfate or lithium hydroxide. Purity, not mining, is often the supply bottleneck.
BauxiteMinerals: The main aluminum ore, a weathered rock rich in aluminum hydroxides. It is refined into alumina, and gallium can be recovered along the way.
Bayer process (Bayer liquor)Minerals: The standard method for refining bauxite into alumina by dissolving it in hot caustic soda. Gallium can be recovered from its process liquor.
Beam and draft (beam, draft, draught)Maritime: A ship's beam is its width at the widest point; its draft is the depth of hull below the waterline. Both limit which ports, canals and berths it can use.
Beam steering (null steering, beamforming)Aerospace: Pointing an antenna's beam in a chosen direction by adjusting the phase of its elements or its physical shape. Null steering does the reverse, placing a blind spot toward a jammer.
BeamwidthAerospace: The angular width of an antenna's main beam, usually measured where power falls to half. Narrow beams reach further but must be pointed more precisely.
Beer distribution gameFinance: A supply chain simulation created at MIT in which players run a retailer, wholesaler, distributor and factory with delayed orders and limited information. It shows the bullwhip effect, where small changes in consumer demand grow into large swings in orders further up the chain.
Behind-the-meter and front-of-meter (behind-the-meter, front-of-the-meter, BTM, FTM, utility-scale storage)Batteries: Behind-the-meter storage sits on a customer's side of the utility meter, such as home or factory batteries. Front-of-meter storage connects directly to the grid and sells services to it.
BenchmarkFinance: A passive reference return against which a strategy is measured.
BeneficiationFinance: Processing that raises the value of ore by removing waste (gangue) minerals, producing a higher-grade concentrate and a waste stream called tailings. Crushing, grinding, flotation and magnetic separation are common steps.
Benthic (benthos, benthic fauna)Minerals: Relating to the seafloor and the animals that live on or in it.
BetaFinance: The sensitivity of a security's return to the market's return. A beta of 1.2 means the security has historically moved about 1.2% for each 1% move in the market.
Beyond visual line of sight (BVLOS)Aerospace: Flying a drone where the pilot cannot see it directly. Long-range delivery and inspection depend on it; in the US it needs a waiver or exemption until a dedicated rule, Part 108, takes effect.
Bilateral aviation safety agreement (BASA, bilateral airworthiness agreement)Aerospace: An agreement under which two countries accept each other's aircraft certification findings, so a design approved in one can be validated more easily in the other.
Bill of materials (BOM)Batteries: The list and cost of every material and part in a product. In batteries the cathode, anode, electrolyte, separator and foils make up most of it.
Binder (PVDF, polyvinylidene fluoride)Batteries: A polymer that holds electrode particles together and to the foil. PVDF, a fluoropolymer processed with a toxic solvent, is standard for lithium-ion cathodes; water-based binders are used for many anodes.
Binder jetting (BJT)Industry: An additive process that glues powder layers together with a liquid binder, then sinters the part in a furnace. It is fast and cheap but parts shrink during sintering.
Biofilter (biological filter, nitrification, nitrifying bacteria)Maritime: A filter colonized by bacteria that convert toxic ammonia from fish waste into nitrite and then much less harmful nitrate, a process called nitrification.
Biofloc technology (BFT, biofloc)Maritime: An aquaculture method that keeps microbial clumps in the water to convert fish waste into protein the animals can eat.
Biofouling (marine growth, fouling)Maritime: The build-up of algae, barnacles, mussels and other organisms on submerged surfaces, which adds drag and weight and can block intakes and sensors.
Biogenic carbonSustainability: Carbon that a plant recently pulled out of the air through photosynthesis, as opposed to fossil carbon locked underground for millions of years. Most frameworks treat biogenic CO₂ released on combustion as neutral, because the next crop reabsorbs it.
Biomass-based dieselSustainability: The U.S. regulatory category covering both FAME biodiesel and renewable diesel (HVO).
Biosecurity (biosecurity measures)Maritime: Measures that keep diseases and pests out of a farm and stop them spreading within or beyond it.
Bitcoin mining (bitcoin miner, crypto mining)Computing: Using specialized computers to compete to add blocks to the bitcoin ledger, earning new coins and fees. Profit depends on bitcoin's price, electricity cost and the efficiency of the machines.
Bits per cell (SLC, MLC, TLC, QLC, penta-level cell)Computing: How many bits each flash memory cell stores. More bits per cell lower cost but reduce speed and endurance. See the table
Black massBatteries: The dark powder left after spent lithium-ion batteries are discharged, shredded and screened. It contains the valuable cathode and anode materials, such as lithium, nickel, cobalt and graphite, and is the main traded recycling intermediate.
Black start (black-start capability)Industry: Restarting a power plant, or the grid, without power from outside after a total blackout. Plants with this ability are valued for grid recovery.
Blade rate (blade passing frequency, blade rate frequency)Maritime: The frequency at which propeller blades pass a fixed point, shaft speed times blade count. It shows up as a modulation in radiated noise.
Blended returnFinance: The weighted sum of constituent returns over a window. THR sector baskets report blended returns from end-of-day closes and stated weights.
Blue carbonMaritime: Carbon captured and stored by coastal and marine ecosystems such as mangroves, seagrass meadows and salt marshes.
Blue economy (ocean economy, blue bonds, blue bond)Maritime: Economic activity based on the oceans, such as shipping, fishing, aquaculture, energy and tourism, ideally managed sustainably.
Blue hydrogenSustainability: Hydrogen made from natural gas with the CO₂ captured and stored. Its real footprint depends on how much CO₂ is actually captured and how much methane leaks upstream. At 93 percent capture and 0.2 percent leakage it cuts emissions about 75 percent versus grey; operating plants such as Quest and Port Arthur capture only 50 to 60 percent.
Blue UAS (Blue UAS List, Blue UAS Cleared List, Blue sUAS)Aerospace: A US defense list of drones and drone components vetted for cybersecurity and NDAA compliance, which military units can buy with fewer approvals. The Defense Innovation Unit created it in 2020; the Defense Contract Management Agency took over its management in December 2025.
BM25Computing: A classic keyword search ranking formula that scores documents by how often query words appear, adjusted for document length. It remains a strong baseline beside vector search.
Boil-offAerospace: The gradual loss of cryogenic propellant as heat leaks into tanks and turns liquid into gas that must be vented. It limits how long cryogenic stages and depots can wait in orbit.
Boost-glide vehicle (hypersonic glide vehicle, HGV, boost-glide)Aerospace: A hypersonic weapon or test vehicle that a rocket boosts to high speed and altitude before it glides unpowered toward its target, maneuvering on the way. It flies lower than a ballistic missile, which makes it harder to track.
Boostback, entry and landing burns (boostback burn, entry burn, landing burn)Aerospace: Engine firings a reusable booster makes after stage separation. The boostback burn reverses its course and the entry burn slows it before the dense lower atmosphere. The landing burn brings it to a stop just above the ground or platform.
Booster (first stage, strap-on booster)Aerospace: The first stage of a rocket, or a smaller motor strapped to its side, that gives most of the thrust at liftoff. On reusable rockets the booster is the part usually recovered and flown again.
Bose-Einstein condensate (BEC)Maritime: A state of matter in which atoms cooled to near absolute zero share one quantum state, used in some advanced atom interferometers.
Boundary layer (boundary-layer heating)Aerospace: The thin layer of air next to a vehicle's surface, slowed by friction. Its behavior sets skin drag and heating; turbulent boundary layers heat a surface far more than smooth, laminar ones.
Bow shockAerospace: The curved shock wave that forms ahead of a blunt body moving faster than sound. Air passing through it is compressed and heated, and at reentry speeds it becomes ionized.
Brain-computer interface (BCI, brain-machine interface)Computing: A system that reads brain signals and turns them into commands for a computer or machine. Non-invasive types use scalp electrodes; invasive types implant electrodes in the brain.
Breathing gas mixtures (heliox, trimix, hydreliox, mixed gas diving)Maritime: Diving gases that replace some or all nitrogen: heliox is helium and oxygen, trimix adds nitrogen, and hydreliox adds hydrogen for extreme depths.
Breguet range equation (Breguet equation)Aerospace: The standard formula for an aircraft's cruise range. Range grows with speed, lift-to-drag ratio and engine efficiency, and with the logarithm of the ratio of starting to ending weight.
Brushless DC motor (BLDC, brushless motor)Aerospace: An electric motor that switches current electronically instead of through brushes, making it efficient and durable. Nearly all small drones use brushless motors with permanent magnets.
Buffer poolSustainability: A reserve of credits that a carbon program sets aside and does not sell, used to cover losses if stored carbon is later released. It works like an insurance fund for reversals.
Bulk sample (bulk sampling)Minerals: A large sample, often tens to thousands of tonnes, mined and processed to test how ore behaves at scale.
Bureau of Industry and Security (BIS)Aerospace: The US Commerce Department agency that administers the EAR and keeps lists of restricted foreign parties, such as the Entity List.
Burst containmentBatteries: The housing that captures fragments if a flywheel rotor fails at speed. It adds mass and cost, and below-ground vaults are often used for safety.
Bushveld Complex (Bushveld, Merensky Reef, UG2, UG2 Reef, Platreef)Minerals: A huge layered intrusion in South Africa that holds most of the world's platinum group metal reserves. Its main ore layers are the Merensky Reef, the UG2 chromitite and the Platreef.
By-product credit (by-product credits, byproduct credit)Minerals: Revenue from secondary metals that is subtracted from the cost of the main metal, lowering its reported unit cost.
By-product metal (by-product, byproduct, companion metal)Minerals: A metal recovered only as a side stream of mining or refining another metal, such as gallium from alumina or indium from zinc. Its supply follows the main metal, not its own price.

C

C-rate (C rate)Batteries: Charge or discharge current expressed relative to capacity. At 1C a full battery discharges in one hour; at 2C in 30 minutes; at C/2 in two hours.
CA-GREETSustainability: The California Air Resources Board's adaptation of GREET, used to certify fuel pathway carbon intensities under the LCFS.
CAAC (Civil Aviation Administration of China)Aerospace: China's civil aviation regulator, responsible for aircraft certification, airlines and airspace use.
Cable plough (plough, cable plow, subsea plough)Maritime: A towed seabed sled that cuts a trench, lays cable into it and covers it in one pass, burying it away from anchors and trawls.
Cable protection zone (cable protection zones, protection zone)Maritime: A sea area where anchoring, trawling or other seabed activities are restricted to protect submarine cables.
Cable ship (cable repair ship, cable-laying ship, cable layer, cable vessel)Maritime: A vessel built to lay, recover and repair submarine cables, with cable tanks, bow sheaves, cable engines and a jointing room for splicing.
CAD, CAM and CAE (CAD, CAM, CAE, computer-aided design, computer-aided manufacturing, computer-aided engineering)Industry: The main engineering software types. Computer-aided design creates the part model; computer-aided manufacturing turns it into machine instructions; computer-aided engineering simulates its behavior.
Calendar life (calendar aging)Batteries: How long a battery lasts with age alone, regardless of use. Heat and high state of charge speed calendar aging, so stored batteries degrade even when idle.
Calendering (roll-pressing)Batteries: Pressing coated electrodes between heavy rollers to a precise thickness and density. It sets how much active material fits in a cell.
Capacity (usable capacity, energy capacity)Batteries: How much charge or energy a battery can store, given in ampere-hours or watt-hours. Usable capacity is less than nameplate capacity because some is held back to protect the cells.
Capacity factorBatteries: A plant's actual output over a period divided by what it would produce running at full power the whole time. Solar typically reaches ≈10–25%; storage owners use it to describe utilization.
Capacity fade (capacity loss, degradation)Batteries: The gradual loss of a battery's usable capacity with cycling and age, caused by side reactions, lost lithium and electrode damage.
Capacity utilization (utilization rate, utilisation)Batteries: Actual output divided by nameplate capacity. Low utilization across an industry signals overcapacity and price pressure.
Capital and operating costsFinance: Capital costs (capex) are the upfront spending to build or expand a project, such as the plant, equipment and mine development. Operating costs (opex) are the recurring costs of running it, often quoted per tonne of ore or per unit of product.
Captive fairingAerospace: A payload fairing that stays attached to the first stage and opens to release the upper stage, instead of separating and falling away. The design lets the fairing return and be reused with the booster.
Capture rateSustainability: The share of a plant's CO₂ actually captured. The nameplate rate is what a plant is designed for; the realized rate is what it achieves, and it is often lower. Retrofits typically capture only the concentrated process stream, not the flue gas from burners.
CARB (California Air Resources Board)Sustainability: California's air-quality and climate regulator, which runs the LCFS and sets its ILUC values using GTAP-BIO.
Carbon accountingSustainability: The practice of measuring, allocating and reporting the greenhouse gases linked to a product, company or activity, using defined rules for what counts, where the boundary sits and which baseline applies. Different rulebooks give different answers for the same physical fuel.
Carbon anode (prebaked anode, consumable anode)Industry: The block of baked carbon that carries current into an aluminum cell and is consumed as it reacts with oxygen, producing CO₂. Anodes must be replaced every few weeks.
Carbon Border Adjustment Mechanism (CBAM)Industry: The EU charge on the carbon in imported cement, iron and steel, aluminum, fertilizers, electricity and hydrogen. Its definitive period began on 1 January 2026 and certificate sales start in February 2027. Importers of under 50 tonnes a year are exempt, except for electricity and hydrogen.
Carbon capture and storage (CCS)Sustainability: Separating CO₂ from an industrial stream and injecting it into deep geological formations for permanent storage. Captured fossil CO₂ lowers emissions but does not remove carbon from the atmosphere.
Carbon debtSustainability: The one-off pulse of carbon released when land is cleared or converted for a fuel crop, from burned or decaying vegetation and disturbed soil. The fuel must then save emissions for years before it has repaid that debt. Converting Southeast Asian peat rainforest to palm releases about 3,452 t CO₂ per hectare, by one widely cited estimate.
Carbon footprint declaration (battery carbon footprint)Batteries: A statement of the life cycle greenhouse gas emissions of a battery, required under EU battery rules for EV and some industrial batteries, followed by performance classes and maximum limits.
Carbon intensity (CI)Sustainability: The lifecycle emissions per unit of fuel energy, usually in grams of CO₂e per megajoule. It is the number that incentive programs such as the LCFS and Section 45Z pay on: the lower the CI, the larger the credit.
Carbon neutral (carbon neutrality)Sustainability: A claim that a product's net lifecycle emissions equal zero. It is a much stronger claim than being lower-carbon than the alternative.
Carbon removal (durable removal)Sustainability: Taking CO₂ out of the atmosphere and storing it for a long time, typically centuries, in geological formations, mineral form or stable materials. Carbon held in short-lived products, such as fuel, does not count.
Carbon-debt payback timeSustainability: The years needed for a biofuel's annual savings to repay the carbon debt from land conversion. It equals the allocated debt divided by the yearly saving per hectare.
Carbon-intensity-priced offtakeSustainability: An offtake whose price rises or falls with the verified carbon intensity of the fuel delivered, rewarding the producer for decarbonizing inputs such as hydrogen.
CarbonatiteMinerals: A rare igneous rock made mostly of carbonate minerals. Carbonatites host many of the largest light rare earth deposits.
CarburizationIndustry: Absorption of carbon into a metal surface at high temperature, which can harden it on purpose or embrittle it in service.
Care and maintenance (placed on care and maintenance)Minerals: Status of a mine or plant that has stopped production but is kept in condition to restart when prices or conditions improve.
Carnot limit (Carnot efficiency)Batteries: The theoretical maximum share of heat that any engine can turn into work, set by its hot and cold temperatures. It caps how much electricity a heat store can return.
Carrier-phase positioning (carrier phase, carrier-phase differential GPS, CDGPS, RTK, real-time kinematic, ambiguity resolution)Maritime: High-precision positioning that measures the phase of the radio carrier wave, not just its code. Resolving whole-cycle ambiguity gives centimeter accuracy.
Cash flowFinance: The movement of cash into and out of a business over a period. The cash flow statement divides it into operating, investing and financing activities.
Cassiterite (SnO₂)Minerals: Tin oxide (SnO₂), the main tin ore mineral, mined from veins and placers.
Cathode (positive electrode)Batteries: The positive electrode of a battery during discharge, where electrons are taken up. In lithium-ion cells the cathode chemistry, such as LFP or NMC, largely sets energy density, cost and the metals needed.
Cathode active material (CAM)Batteries: The finished cathode powder, such as LFP or NMC, sold to cell makers. It is made from precursor and lithium compounds and is the largest single cost in most lithium-ion cells.
Cathodic protection (sacrificial anode, impressed current cathodic protection, ICCP)Maritime: Slowing corrosion of submerged steel by making it the cathode of an electrical circuit, using sacrificial zinc or aluminum anodes or an impressed current.
Cavitation (propeller cavitation, cavitation noise)Maritime: The formation and collapse of vapor bubbles where water pressure drops, as on fast-turning propeller blades. It is the main source of a ship's broadband noise and can erode metal.
CBRS (Citizens Broadband Radio Service)Computing: Citizens Broadband Radio Service, a shared US band at 3.55–3.7 GHz that companies can use for private LTE and 5G networks.
CCLUB (Carbon Calculator for Land Use and Land Management Change from Biofuels Production)Sustainability: Argonne's module that attaches land-use emissions to GREET results. It applies 38.1 t CO₂e per hectare per year for peat oxidation and gives about 7.9 g CO₂e/MJ of ILUC for soybean biodiesel.
Cell cost (cell cost per kWh)Batteries: The cost of producing one kilowatt-hour of cell capacity, given in $/kWh. Materials make up most of it, so metal prices move it as much as factory efficiency does.
Cell voltage (nominal voltage, open-circuit voltage, OCV)Batteries: The electrical potential difference between a cell's electrodes, set mainly by its chemistry. Nominal lithium-ion voltages are ≈3.2 V for LFP and ≈3.6–3.7 V for NMC; sodium-ion cells sit near 3 V.
Cell-to-pack (CTP, cell-to-body, CTB, cell-to-chassis)Batteries: A pack design that places cells directly in the pack without modules, raising the share of pack mass and volume that stores energy. Cell-to-body designs go further and make the pack part of the vehicle structure.
Cemented carbide (hardmetal, tungsten carbide, carbide tools)Minerals: Tungsten carbide grains bound with cobalt into an extremely hard, tough material used for cutting tools, drill bits and wear parts.
Central estimateSustainability: The single most representative value within a range of plausible results, used as the headline figure. The range around it shows how much the answer depends on assumptions.
CerradoSustainability: The vast tropical savanna of central Brazil, rich in below-ground carbon and a major frontier of soybean expansion.
Certification basisAerospace: The set of regulations and special conditions a specific design must meet to earn its type certificate, agreed between the applicant and the regulator.
Certification scheme (voluntary scheme)Sustainability: A private program recognized by the European Commission to audit and certify that biofuel feedstocks meet sustainability and waste-status rules. ISCC is the largest. Critics point to weak audits at the point where waste status is attested.
CerulogySustainability: A UK consultancy specializing in the sustainability of alternative fuels, whose analyses on waste and residue supply are cited by NGOs and regulators.
Chain of custodySustainability: The documented trail that follows a material from origin to final product, showing who held it and what claims travel with it. Mass balance is the most common chain-of-custody model for biofuels.
Chamber pressureAerospace: The pressure inside a rocket engine's combustion chamber. Higher pressure packs more thrust into a smaller, lighter engine and improves efficiency, especially at sea level.
Changeover (setup reduction, setup time)Industry: Switching a machine or line from one product to another, including retooling, reprogramming and checking the first parts. Shorter changeovers make small batches economic.
Chemical mechanical planarization (CMP, CMP slurry, chemical mechanical polishing)Industry: Polishing a wafer flat with a chemical slurry and a rotating pad between chip-making steps.
Chemically amplified resist (CAR)Computing: A photoresist in which each absorbed photon releases an acid that triggers many chemical reactions, raising sensitivity. It is standard for deep ultraviolet and early EUV lithography.
Chinese antimony export controls (Announcement No. 33, Announcement No. 46, antimony export ban)Minerals: China has required licences to export antimony ores, metal and oxides since 15 September 2024. A December 2024 policy of refusing US-bound licences was suspended in November 2025 for a year; exports for US military use stay barred.
Chinese rare earth export controls (MOFCOM Announcement No. 18, Announcement No. 18, Announcement No. 61, Announcement No. 70, rare earth export licensing)Minerals: Since April 2025 China has required licences to export seven medium and heavy rare earths, including dysprosium and terbium, and their oxides, alloys and compounds. A wider October 2025 expansion was suspended in November 2025 for one year.
Chiplet (chiplets)Computing: A small die designed to be combined with others in one package, instead of building one large chip. Chiplets improve yield and let different parts use different processes.
CHIPS and Science Act (CHIPS Act)Computing: The 2022 US law that funds domestic semiconductor manufacturing and research with ≈$52 billion and created the Section 48D investment tax credit.
Chokepoint (maritime chokepoint, choke point)Maritime: A narrow sea passage, such as a strait or canal, through which much shipping must pass, so closure or attack can disrupt trade.
Chromitite (chromite)Minerals: A rock made mostly of the chromium mineral chromite. Chromitite reefs such as UG2 carry platinum group metals but are harder to smelt.
Chunking (semantic chunking)Computing: Splitting documents into smaller passages before embedding them for retrieval. Chunk size and boundaries strongly affect retrieval quality.
Cislunar space (cislunar)Aerospace: The region between Earth and the Moon, including lunar orbits. Interest in it is growing for exploration, commerce and military awareness.
Clarion-Clipperton Zone (CCZ, Clarion-Clipperton Fracture Zone)Minerals: A vast Pacific abyssal region between Hawaii and Mexico holding the richest known nodule fields, where most seabed exploration contracts lie.
Class VI well (Class VI permit, Class VI injection well)Industry: The US Environmental Protection Agency permit class for wells that inject CO₂ underground for long-term storage.
Closed-loop recycling (closed loop)Batteries: Recycling in which recovered materials go back into the same product, such as new battery cells.
Cloud computingComputing: Renting computing, storage and software over the internet from providers instead of owning hardware.
CLTC (China Light-duty Vehicle Test Cycle)Batteries: The China light-duty vehicle test cycle, used to rate electric-vehicle range in China. It gives higher range figures than the European WLTP or US EPA cycles for the same car.
CMMC (Cybersecurity Maturity Model Certification)Aerospace: The US Defense Department program requiring contractors to meet, and prove, cybersecurity standards for the information they handle, at Levels 1 to 3. It began phasing into contracts on 10 November 2025.
CMOS (complementary metal-oxide-semiconductor)Computing: Complementary metal-oxide-semiconductor, the transistor technology used in almost all digital chips. Its low idle power made modern processors possible.
CNC controller (machine tool controller)Industry: The computer that drives a machine tool's motors from the part program. A few vendors supply most of the world's controllers, which makes them a supply-chain chokepoint.
CNC machining (CNC, computer numerical control, numerical control)Industry: Cutting parts from metal or plastic with machines whose tools are moved by computer numerical control, following a programmed toolpath. It is the backbone of precision manufacturing.
Co-location (behind-the-meter co-location)Computing: Placing a large load, such as a data center, directly at a power plant to draw power behind the meter. Regulators scrutinize it because it can shift costs to other grid users.
Co-packaged optics (CPO)Computing: Placing optical engines in the same package as a switch or processor chip, instead of in pluggable modules at the front panel. It cuts power and raises bandwidth density.
Co-processingSustainability: Feeding a share of vegetable oil or waste fat into an existing petroleum refinery unit alongside crude-derived feed, rather than building a dedicated plant. The renewable share of the output is tracked by accounting rules.
Co-productSustainability: A useful output produced alongside the main product, such as soybean meal from crushing, glycerol from biodiesel, or propane and naphtha from HVO. Co-products share the upstream emissions through allocation or earn credits through system expansion.
CO₂e (carbon dioxide equivalent)Sustainability: A common unit that expresses different greenhouse gases as the amount of CO₂ that would cause the same warming. One gram of N₂O counts as 273 to 298 g CO₂e depending on the factor set used.
Cobalt-freeBatteries: Describes cathodes that use no cobalt, such as LFP, LMFP and some high-nickel or manganese-rich designs. Removing cobalt cuts cost and reliance on mining in the Democratic Republic of the Congo.
Cobalt-rich ferromanganese crusts (ferromanganese crusts, cobalt crusts, cobalt-rich crusts)Minerals: Thin metal-rich coatings on seamount rock, carrying cobalt, nickel, manganese and rare earths.
Coefficient of performance (COP)Batteries: Heat delivered by a heat pump divided by the electricity it uses. Values of ≈3–4 are typical; resistive heating has a value of 1.
Coercivity (Hcj, intrinsic coercivity)Minerals: A magnet's resistance to being demagnetized by opposing fields or heat. Heavy rare earths raise it.
Coherent optics (coherent DSP)Computing: Optical links that encode data in both the amplitude and phase of light, recovered with a digital signal processor. They carry the most data over long distances.
CokingAerospace: Solid carbon deposits left when hydrocarbon fuel overheats in engine passages or cooling channels. Coking clogs those channels, which limits how hot kerosene-fueled engines can run and how often they can be reused.
Cold atoms (laser-cooled atoms, ultracold atoms, magneto-optical trap, MOT)Maritime: Atoms cooled by lasers to millionths of a degree above absolute zero, where their quantum behavior can be used for precise sensing and timing.
Cold-flow propertiesSustainability: How well a fuel keeps flowing in cold weather without forming wax crystals that clog filters. Measured by cloud point and cold filter plugging point, they are the main reason HVO is isomerized.
Cold-gas thrusterAerospace: A simple thruster that releases stored compressed gas, such as nitrogen, through a nozzle without burning it. It gives little thrust but is reliable for small attitude adjustments.
Collaborative Combat Aircraft (CCA)Aerospace: The US Air Force program to buy uncrewed, autonomous combat aircraft that fly with crewed fighters. It runs in increments; in June 2026 the Air Force ordered both Increment 1 designs, the FQ-42A and FQ-44A, into production.
Colocation (colo)Computing: Renting space, power and cooling in a data center for customer-owned servers.
Coltan (columbite-tantalite, tantalite, columbite)Minerals: A dark ore mixing columbite and tantalite, minerals rich in niobium and tantalum. Much is dug by hand in central Africa.
Combat radiusAerospace: How far a military aircraft can fly out, carry out its mission and return without refueling. It is less than half its one-way range because of time on station and fuel reserves.
Combinatorial optimization (combinatorial optimisation)Computing: Finding the best option among a huge but finite set of combinations, such as delivery routes, schedules or chip layouts. Many such problems are NP-hard, so solvers rely on heuristics.
Combined heat and power (CHP, cogeneration, co-generation)Industry: Generating electricity and useful heat together from one plant, raising overall efficiency.
Command and control (C2)Aerospace: The authority, communications and systems commanders use to direct forces. For drones it also means the data link that carries control commands to the aircraft.
Commerce Control List (CCL)Aerospace: The EAR list of controlled dual-use items, each identified by an export control classification number that determines which destinations need a license.
Commercial Lunar Payload Services (CLPS)Aerospace: A NASA program that buys delivery of science instruments and technology to the Moon on commercial landers, accepting more risk for lower cost than traditional missions.
Commercial solutions openingAerospace: A US defense solicitation that invites companies to propose commercial technologies against broad problem statements, often leading to other transaction agreements.
Comminution (crushing and grinding, SAG mill, ball mill, grinding)Minerals: Crushing and grinding ore to free mineral grains from waste. It is usually the largest energy user in a processing plant.
Common heritage of mankind (common heritage of humankind)Minerals: The legal principle that certain resources, such as seabed minerals in the Area, belong to humanity as a whole and cannot be claimed by one state.
Common operating pictureAerospace: A single shared display of friendly forces, threats and other data, built from many sensors, so that every user sees the same situation.
Compound helicopterAerospace: A helicopter that adds wings, extra propellers or both to share the load at high speed, letting it fly faster than a conventional helicopter.
Compressed air energy storage (CAES)Batteries: Storing energy by compressing air into caverns or tanks and later expanding it through turbines. Heat lost in compression lowers efficiency unless it is captured and reused.
Computational lithography (OPC, optical proximity correction, ILT, inverse lithography technology, SMO, source-mask optimization, curvilinear masks)Computing: Using simulation and optimization to adjust mask shapes and light sources so the printed pattern matches the design. It includes optical proximity correction, inverse lithography and source-mask optimization.
Computer vision (machine vision)Computing: AI that interprets images and video, for tasks such as detecting objects, reading text or inspecting parts.
Concentrate (mineral concentrate, preconcentrate)Minerals: The upgraded product of mineral processing, with much higher metal content than ore, sold to smelters or refiners. Tungsten concentrate is typically ≈65% WO₃.
Conditional value at risk (CVaR)Finance: The average loss in the worst cases beyond the VaR threshold, also called expected shortfall. It describes how bad losses are when they do exceed VaR.
Conflict minerals (3TG, conflict mineral)Minerals: Minerals whose trade may finance armed groups or abuses, defined in US and EU rules as tin, tantalum, tungsten and gold, known as 3TG.
Conjunction (conjunction assessment, collision avoidance)Aerospace: A predicted close approach between two objects in orbit. Operators assess the collision probability and may fire thrusters to move away; large constellations make many thousands of such maneuvers.
Consequential accounting (consequential LCA)Sustainability: A way of measuring emissions that asks what changes in the world because of an extra unit of demand. It captures ripple effects such as new land clearing or former users of a waste switching to another material.
Consolidated leverage ratioFinance: A measure, usually defined in a loan agreement, that divides the total debt of a company and its subsidiaries by their combined EBITDA. Lenders set a maximum level as a covenant, and breaching it can trigger default provisions.
Contained metal (contained metal content, in-situ metal, gross in-situ value)Minerals: The total metal in a deposit or product, found by multiplying tonnage by grade, before any losses in mining and processing.
Container terminal (container port)Industry: The part of a port where container ships are loaded and unloaded and boxes are stored and moved to trucks and trains.
Context window (context length, long context)Computing: The maximum amount of text, in tokens, a language model can consider at once, including the prompt and its answer. Longer windows cost more compute and models often use the middle poorly.
Continued safe flight and landing (CSFL)Aerospace: A certification requirement that an aircraft can keep flying and land safely after specified failures, such as losing a motor or battery. It replaces autorotation as the safety case for many eVTOLs.
Continuing resolutionAerospace: A stopgap US law that funds agencies at prior-year levels when Congress has not passed annual appropriations. It usually bars new programs, called new starts, and production increases, which delays defense work.
Contract ceiling (ceiling value)Aerospace: The maximum value a contract allows over its life if all options and orders are used. Actual spending is often far lower, so ceilings overstate likely revenue.
Contract manufacturing (manufacturing-as-a-service, on-demand manufacturing)Industry: Making parts or products for another company to its design. Online platforms now quote and route machining and printing jobs to networks of shops.
Contribution to returnFinance: A constituent's weight at the start of a window multiplied by its return over the window. The contributions of all constituents add up to the blended return.
Control moment gyroscope (CMG)Aerospace: A spinning wheel on a tilting mount that produces large turning forces when its axis is tilted. Large spacecraft, such as space stations, use it to point quickly without propellant.
Controlled reception pattern antenna (CRPA)Aerospace: A GPS antenna array that electronically places nulls toward jamming sources while keeping reception from satellites, making navigation harder to jam.
Controlled unclassified information (CUI)Aerospace: Sensitive US government information that is not classified but must be protected under set rules, such as export-controlled technical data. Contractors who handle it generally need CMMC Level 2 or higher.
Controlled-environment agriculture (CEA, vertical farming, vertical farm, indoor farming)Maritime: Growing crops in enclosed, climate-controlled structures such as greenhouses and vertical farms, with controlled light, temperature, humidity and nutrients.
Convergence zone (convergence zones)Maritime: A ring at ≈50–60 km intervals where deep-refracted sound returns to the surface, allowing detection at long range in deep water.
Converted refinery and standalone plantSustainability: A converted refinery is a former petroleum refinery rebuilt to process lipids into HVO, often keeping its gas-fired hydrogen reformer; a standalone plant is built new for the purpose. Examples of conversions include Phillips 66 (NYSE:PSX) at Rodeo and Eni (BIT:ENI) at Venice and Gela.
Coordinated Universal Time (UTC)Maritime: The world's reference time scale, kept by atomic clocks and adjusted with leap seconds. Networks, power grids and finance synchronize to it.
Copper electroplating (damascene, electroplating, through-silicon via, TSV)Industry: Depositing copper from a plating bath to form a chip's wiring, as in the damascene process, or to fill through-silicon vias in stacked chips.
Core lifecycle valueSustainability: CORSIA's term for the direct, attributional part of a fuel's lifecycle emissions, excluding ILUC. The ILUC value is added separately.
Core loss (iron loss, eddy-current loss, hysteresis loss)Industry: The energy lost as heat in a magnetic core each cycle, from hysteresis and eddy currents. Lower core loss means more efficient transformers and motors.
Corpus poisoning (index poisoning, data poisoning)Computing: Planting false or malicious documents in a retrieval collection so that an AI system retrieves and repeats them.
CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation)Sustainability: The International Civil Aviation Organization's global scheme, adopted in 2016, under which airlines offset growth in international aviation emissions or cut them with eligible lower-carbon fuels. Its lifecycle values combine a core value with an ILUC value, amortized over 25 years against an 89 g CO₂e/MJ jet-fuel baseline.
CORSIA eligible fuelSustainability: A sustainable or lower-carbon aviation fuel that meets CORSIA's sustainability criteria, including at least 10 percent lower lifecycle emissions than the 89 g baseline, which puts the threshold near 80 g.
COSPAR (Committee on Space Research)Aerospace: The international Committee on Space Research, which sets the planetary protection guidelines most space agencies follow.
Cost deltaFinance: The difference in cost between two producers, processes or scenarios, such as a project's unit cost compared with the marginal producer's. A wide cost delta indicates how much a price can fall before a producer stops being profitable.
Cost of ownership (CoO, cost per wafer pass)Computing: The full cost of running a manufacturing tool over its life, including price, throughput, uptime, consumables and yield, usually expressed per wafer pass.
Cost per kilogram (price per kilogram)Aerospace: Launch price divided by the payload mass a vehicle can deliver to a given orbit. It is the standard way to compare launch costs, though it flatters large rockets that often fly partly empty.
Cost per seat-mile (cost per available seat-mile, CASM)Aerospace: An aircraft's operating cost divided by the number of seats times the miles flown. It lets operators compare aircraft of different sizes.
Cost-plus contract (cost-reimbursement contract, cost-plus-fee)Aerospace: A contract that repays a contractor's allowable costs plus a fee. It shifts cost risk to the government and is common for risky development work.
Cost, insurance and freight (CIF)Industry: A trade term in which the seller pays for goods, insurance and shipping to the destination port. Import duties are often calculated on CIF value.
Coulombic efficiencyBatteries: The share of charge put into a cell that comes back out on discharge. Small losses compound over hundreds of cycles, so even 99.9% efficiency matters for long-life cells.
Counter-UAS (C-UAS, counter-drone)Aerospace: Systems that detect, track and defeat hostile drones, using jamming, interceptors, guns, lasers or high-power microwaves.
CounterfactualSustainability: What would have happened without the activity being assessed. A waste's counterfactual is its fate if the fuel plant did not take it, for example animal feed, soap or disposal.
Cover cropSustainability: A crop grown mainly to protect or improve soil between cash crops, rather than for sale. Some oilseed cover crops can also yield fuel feedstock. Several U.S. states assign cover-crop oils zero ILUC.
CPU (central processing unit)Computing: Central processing unit, the general-purpose processor that runs operating systems and most software. It handles varied tasks well but few operations in parallel.
Crack spread (crack spreads, 3-2-1 crack spread)Industry: The difference between the price of refined products and the crude oil they come from, a quick proxy for refining profitability. A common form is the 3-2-1 spread.
Cracking (acid bake, sulfuric acid bake, caustic cracking, caustic conversion, acid digestion)Minerals: Breaking down a rare earth or similar concentrate with strong acid or alkali so its metals can be dissolved. Sulfuric acid baking and caustic conversion are common routes.
Cradle-to-graveSustainability: A lifecycle boundary that runs from raw material extraction or cultivation through processing and use to final disposal or combustion. For fuels the equivalent term is well-to-wheel.
Crane moves per hour (moves per hour, gross crane rate)Industry: The number of containers a crane lifts each hour, the main measure of terminal productivity.
Critical density (cutoff density)Aerospace: The electron density at which a plasma's natural frequency equals a given radio frequency, so the plasma blocks that signal. Higher frequencies need denser plasma to be blocked.
Critical dimension (CD, CDU, critical dimension uniformity)Computing: The width of the smallest feature in a pattern that must be controlled tightly, such as a transistor gate. Critical dimension uniformity measures how consistent it is across the wafer.
Critical IT load (critical IT capacity, IT load, IT MW)Computing: The power used by a data center's computing equipment itself, excluding cooling and other overhead. Data center capacity is usually quoted in megawatts of IT load.
Critical mineral (critical material)Finance: A mineral or material considered essential to economic or national security whose supply is at risk of disruption. Governments publish official lists, such as the US Geological Survey critical minerals list.
Critical Raw Materials Act (CRMA, Regulation (EU) 2024/1252)Batteries: The 2024 EU law, Regulation (EU) 2024/1252, on securing critical raw materials. Its 2030 benchmarks call for EU extraction of 10%, processing of 40% and recycling of 25% of EU needs, and no more than 65% from any one non-EU country.
Critical undersea infrastructure (undersea infrastructure, subsea infrastructure)Maritime: Subsea cables, pipelines and power links whose damage would disrupt communications, energy or economies, increasingly treated as a security target.
Crop oil (crop-oil HVO)Sustainability: Vegetable oil pressed from crops grown for the purpose, such as rapeseed, canola, soybean, sunflower and palm, as opposed to wastes and residues. Crop-oil pathways carry fertilizer, soil N₂O and land-use burdens that waste pathways avoid.
Crude distillation unit (CDU, atmospheric distillation, crude distillation column)Industry: The first and largest unit in a refinery, which heats crude oil and separates it by boiling range into gases, naphtha, kerosene, diesel and residue. Its size sets a refinery's nameplate capacity.
Crude oil benchmarks (Brent, WTI, West Texas Intermediate)Industry: Reference grades used to price oil worldwide. Brent from the North Sea and WTI from the US are the main ones; local grades trade at premiums or discounts to them.
Crude tall oilSustainability: A by-product of the kraft pulping process that turns pine wood into paper pulp. It has an established market in pine chemicals, so diverting it to fuel carries displacement risk.
CrushingSustainability: Breaking oilseeds to separate oil from the solid meal. It can be done by mechanical pressing, by solvent extraction with hexane, or both in sequence; solvent extraction recovers more oil.
Cryogenic computing (cryogenic CMOS, cryo-CMOS)Computing: Running computer hardware at very low temperatures, from liquid nitrogen's 77 K to near absolute zero, to cut resistance and leakage. Cooling costs can cancel much of the gain.
Cryogenic propellant (cryogenic propellants)Aerospace: A propellant stored as a very cold liquid, such as liquid oxygen, methane or hydrogen. Cryogenics give high performance but warm up and boil off over time, which limits long missions.
Cryolite (Na₃AlF₆, smelting bath)Industry: Sodium aluminum fluoride (Na₃AlF₆), the molten salt bath in which alumina is dissolved for smelting.
Crypto-agility (cryptographic agility)Computing: Designing systems so their cryptographic algorithms can be swapped quickly, for example to post-quantum methods, without rebuilding the system.
Curie temperature (Curie point)Minerals: The temperature above which a magnetic material loses its magnetism. Working limits are set well below it.
Current collector (copper foil, aluminum foil)Batteries: The metal foil on which electrode material is coated and through which current flows out of the cell. Lithium-ion anodes need copper; sodium-ion cells can use cheaper, lighter aluminum on both sides.
Current efficiencyIndustry: The share of electric current in an electrolytic cell that produces metal rather than being lost to side reactions. Modern aluminum cells reach ≈95%.
Curtailment (curtailed electricity)Batteries: Deliberately reducing output from wind or solar plants because the grid cannot use or carry the power. Curtailed electricity is cheap or free to store.
Customer acquisition cost (CAC)Finance: The total sales and marketing spend needed to win new customers, divided by the number of customers gained. It is usually compared with the revenue or profit a customer brings in over their lifetime.
Cut-and-fill mining (drift-and-fill, cut and fill, backfill, paste backfill)Minerals: An underground method that mines ore in horizontal slices and fills each void, often with cemented tailings, before taking the next slice.
Cut-offSustainability: A decision to leave small or hard-to-measure inputs out of an assessment. ISO 14044 permits cut-offs when they are documented.
Cut-off grade (cutoff grade)Minerals: The lowest grade at which rock is counted as ore in a resource or mine plan. Rock below it is treated as waste.
Cycle life (cycle count)Batteries: The number of full charge-discharge cycles a battery delivers before its capacity falls to a set threshold, commonly 80% of the original. Test conditions such as depth of discharge and temperature change the result.
Cyclic and collective pitch (cyclic, collective)Aerospace: The two main helicopter rotor controls. Collective changes the pitch of all blades together to climb or descend; cyclic varies pitch around each rotation to tilt the rotor and steer.
Cylindrical, prismatic and pouch cells (cylindrical cell, prismatic cell, pouch cell, 21700, 2170, 4680)Batteries: The three main cell formats. Cylindrical cells are wound in metal cans, such as the 21700 or 4680 sizes; prismatic cells are rectangular cans; pouch cells are stacked layers sealed in soft foil.

D

Dark factory (lights-out manufacturing, lights-out factory)Industry: A plant that runs production for long periods with no people on the floor, so lights and heating can stay off. Few plants do this continuously; most run unattended only for overnight or weekend windows.
DARPA (Defense Advanced Research Projects Agency)Aerospace: The US Defense Department agency that funds high-risk, high-payoff research, often through short, focused programs with industry and universities.
Data center (datacenter, data centre)Computing: A facility housing servers, storage and networking, with the power and cooling to run them. AI data centers draw hundreds of megawatts.
Data converter (DAC, ADC, digital-to-analog converter, analog-to-digital converter)Computing: A circuit that converts between analog and digital signals. Digital-to-analog and analog-to-digital converters can dominate the power of analog and photonic computers.
Data historian (process historian)Computing: Software that records time-stamped readings from plant sensors and controllers for analysis and compliance.
Data lake (data lakes)Computing: A large store that holds raw data in its original formats, from sensor logs to documents, for later analysis.
Data residency (data localization, data localisation)Computing: A requirement that data be stored and processed within a particular country or region, often for legal or security reasons.
Data sovereigntyComputing: The principle that data is subject to the laws of the country where it is stored or whose citizens it concerns. It drives demand for local clouds and on-premises AI.
DAYCENT and DNDCSustainability: Process-based models that simulate soil carbon and nitrogen cycles day by day to estimate site-specific N₂O emissions. DAYCENT is the daily version of the CENTURY model; DNDC stands for DeNitrification-DeComposition.
De minimis rule (de minimis threshold, 0.1% rule)Minerals: In export controls, a threshold below which a foreign-made product's controlled content is ignored; above it, the exporting country's controls apply.
Dead reckoning (DR navigation)Maritime: Estimating position from a last known fix plus measured speed, heading and time.
Deadweight tonnage (deadweight, DWT, dwt)Maritime: The total weight a ship can safely carry, including cargo, fuel, water, stores and crew, in tonnes. It measures carrying capacity, not the ship's own weight.
DebtFinance: Borrowed money that must be repaid, usually with interest, such as bank loans and bonds. Lenders rank ahead of shareholders if a company fails.
Debye lengthAerospace: The distance over which a plasma screens out an electric field. It sets the thickness of the sheath between a plasma and a surface.
Decarboxylation and decarbonylationSustainability: Reaction routes that strip oxygen from fats by removing it as CO₂ (decarboxylation) or CO (decarbonylation). They use less hydrogen than hydrodeoxygenation but lose one carbon atom per chain, lowering yield.
Decibel (dB, dBA, A-weighted decibel)Aerospace: A logarithmic unit for ratios of power or intensity: +3 dB is ≈2× the power and +10 dB is 10×. A-weighted decibels (dBA) adjust sound levels to match human hearing and are used for aircraft noise.
Decoherence (coherence time, T1, T2)Computing: The loss of a qubit's quantum state through interaction with its surroundings. Coherence times, called T1 and T2, measure how long a qubit keeps its state.
Decomposition potential (decomposition voltage)Minerals: The minimum voltage needed to split a compound by electrolysis. Oxides with higher values, such as calcium and magnesium oxide, are reduced last.
Dedicated launchAerospace: A launch bought by a single customer, who sets the orbit and launch date. It costs more per kilogram than a rideshare but avoids waiting for, or compromising with, other payloads.
Deep learningComputing: Machine learning with neural networks of many layers, trained on large datasets. It drives modern speech, vision and language systems and needs large amounts of compute.
Deep Seabed Hard Mineral Resources Act (DSHMRA, commercial recovery permit, NOAA exploration licence, NOAA exploration license)Minerals: A 1980 US law under which NOAA licenses US citizens to explore and mine the deep seabed beyond national jurisdiction. A January 2026 NOAA rule allows one combined application for both.
Deep ultraviolet lithography (DUV, ArF, KrF, ArF immersion, 193i, i-line)Computing: Lithography using 248 nm krypton fluoride or 193 nm argon fluoride lasers. Immersion versions place water between lens and wafer to sharpen resolution; with multipatterning they reach ≈7 nm-class nodes.
Default value, typical value and actual valueSustainability: Three ways a regulator can assign a fuel's emissions. A typical value is a representative estimate; a default value is a deliberately conservative version of it that producers may use without their own data; an actual value is calculated from a producer's own verified data.
Defense Autonomous Warfare Group (DAWG)Aerospace: A US defense organization formed in 2025 within Special Operations Command to scale up autonomous and uncrewed systems. It took over the Replicator initiative's portfolio in November 2025.
Defense industrial base (DIB)Industry: The companies and facilities that design and make military equipment and the materials and parts it depends on.
Defense Innovation Unit (DIU)Aerospace: A US Defense Department organization that helps the military adopt commercial technology quickly, often through other transaction agreements.
Defense Logistics Agency (DLA, DLA Strategic Materials)Industry: The US Defense Department agency that buys supplies for the military. Its Strategic Materials office manages the National Defense Stockpile.
Defense Production Act Title III (DPA Title III, Defense Production Act)Aerospace: A US authority that lets the Defense Department fund, lend to or guarantee domestic production of materials and components critical to national defense.
Delta-v (Δv, delta v)Aerospace: The total change in velocity a spacecraft can achieve with its propellant, used as the budget for planning a mission. Reaching low Earth orbit from the ground takes ≈9.4 km/s once gravity and drag losses are counted.
Demand response (demand-response, curtailment credits)Computing: Paying large electricity users to cut consumption when the grid is strained. Data centers and bitcoin miners earn credits by curtailing.
DEMON analysis (DEMON)Maritime: Detection of envelope modulation on noise, a technique that extracts propeller blade rate from broadband noise to estimate shaft speed and blade count.
Dendrite (lithium dendrite, dendrites)Batteries: A needle-like metal growth that can form on an anode during charging, especially with lithium metal or at high charge rates. Dendrites can pierce the separator and short-circuit the cell.
Dense and sparse retrieval (dense retrieval, sparse retrieval, hybrid retrieval, hybrid search)Computing: Dense retrieval matches queries to documents by embedding similarity; sparse retrieval matches on keywords, as BM25 does. Hybrid retrieval combines both.
Deorbit (deorbit burn)Aerospace: To lower a spacecraft's orbit until it reenters the atmosphere, usually by firing an engine against the direction of travel. Satellites are deorbited at end of life to limit debris.
Depth of discharge (DoD)Batteries: The share of a battery's capacity used in a cycle. Deeper discharges extract more energy per cycle but usually shorten cycle life, so warranties often state cycles at a given depth.
Desalination (reverse osmosis, RO, seawater desalination, solar still, solar desalination)Maritime: Removing salt from seawater or brackish water to make fresh water, mainly by reverse osmosis or thermal distillation. Reverse osmosis uses ≈3–4 kWh per cubic metre of seawater.
Design Assurance Level (DAL, DAL A)Aerospace: A rating from A to E for how severe the effect of a software or hardware failure would be, from catastrophic (A) to none (E). Level A demands the most rigorous development and verification.
Design for disassembly (design-for-disassembly, design for recyclability, design-for-recyclability)Batteries: Designing a product so it can be taken apart easily for repair, reuse or recycling, for example with removable fasteners instead of glue.
DFARS (Defense Federal Acquisition Regulation Supplement)Aerospace: The US Defense Department's supplement to the Federal Acquisition Regulation, adding defense-specific contract rules. Its clauses restrict sourcing of specialty metals, certain magnets and some Chinese-made components.
DFARS 252.225-7052 (252.225-7052, 10 U.S.C. 4872, 10 U.S.C. 2533c)Minerals: The US defense contract clause barring NdFeB and samarium-cobalt magnets, tantalum and tungsten from China, Russia, Iran and North Korea. From 1 January 2027 it covers every stage from mining to finished product.
Die yield (wafer yield, yield ramp)Computing: The share of chips on a wafer that work. It falls as chips get larger and as processes get newer, which is why chiplets help.
Diesel benchmarkSustainability: The declining carbon-intensity target that diesel substitutes are measured against under California's LCFS. Crop-oil volumes above the program's 20 percent cap are assigned the benchmark intensity and earn no credit.
Diffractive neural network (D²NN, diffractive optical neural network)Computing: An optical system of patterned layers that diffract light so the output pattern computes a neural network's result as light passes through.
Digital Omnibus on AI (Regulation (EU) 2026/1744, AI omnibus)Computing: Regulation (EU) 2026/1744, in force from July 2026, which amends the EU AI Act. It postpones high-risk obligations to 2 December 2027 for Annex III systems and to 2 August 2028 for Annex I systems.
Digital threadIndustry: A linked flow of data about a product from design through manufacture, inspection and service, so every stage works from the same records.
Digital twin (digital twins, urban digital twin)Computing: A live digital model of a physical asset, process or system, kept up to date with sensor data and used to simulate, monitor and predict its behavior.
Dilution of precision (DOP, GDOP, HDOP, PDOP)Maritime: A factor showing how the geometry of satellites or transmitters magnifies ranging errors into position error. Lower is better.
Dilution refrigeratorComputing: A cryogenic cooler that reaches a few thousandths of a degree above absolute zero by mixing two helium isotopes. Superconducting quantum computers run inside one.
Diminishing value (declining balance)Finance: Depreciation calculated as a fixed percentage of an asset's remaining value each year, so the charge falls over time. The term is common in Australian and New Zealand tax practice.
Direct emissionsSustainability: Emissions that come from the supply chain's own physical steps, such as farming, fertilizer, processing, hydrogen and transport. They exclude market-driven effects such as indirect land-use change.
Direct land-use change (dLUC)Sustainability: Emissions from converting a specific plot to grow the feedstock, such as clearing forest for a plantation. It is traceable to the supply chain, unlike indirect land-use change.
Direct operating cost (DOC)Aerospace: The costs of flying an aircraft that vary with its use, such as energy or fuel, crew, maintenance and fees, usually given per flight hour or per seat-mile. Definitions differ on whether ownership costs are included.
Direct recycling (direct cathode recycling, relithiation)Batteries: Recovering cathode material with its crystal structure intact and restoring it, rather than breaking it down to metals. It could save energy and cost but must handle many cathode chemistries.
Direct-to-device (direct-to-cell, D2D, direct-to-handset, direct-to-phone)Aerospace: Satellite service that connects directly to ordinary mobile phones, without a dish or special terminal. It needs very large antennas in orbit and spectrum shared with or leased from mobile operators.
Directed energy deposition (DED, wire arc additive manufacturing, WAAM)Industry: An additive process that melts metal wire or powder as it is fed into a laser, electron beam or arc. It builds or repairs large parts quickly but with coarser detail.
Directed self-assembly (DSA, block copolymer, BCP)Computing: Using block copolymers, molecules made of two incompatible parts, that naturally arrange into fine regular patterns guided by a coarser printed template. It can multiply pitch or repair patterns.
Directive (EU) 2018/2001 (RED II)Sustainability: The recast Renewable Energy Directive that set EU renewable energy rules for 2021 to 2030, including the lifecycle calculation method in Annex V.
Directive (EU) 2023/2413 (RED III)Sustainability: The 2023 amendment to RED II. It raised the EU's binding 2030 renewable energy target to 42.5 percent and set transport goals of either a 14.5 percent cut in greenhouse-gas intensity or a 29 percent renewable share. It keeps RED II's 94 g comparator, energy allocation and the Annex V values, and caps food and feed crop biofuels.
Directorate of Defense Trade Controls (DDTC)Aerospace: The US State Department office that administers ITAR, including registrations, licenses and enforcement.
Discounted cash flow (DCF)Finance: A valuation method that estimates the value of a business today by projecting its future cash flows and discounting them at a rate that reflects their risk. The result is highly sensitive to the growth, margin and discount rate assumptions.
Disk loadingAerospace: Aircraft weight divided by the total area swept by its rotors. Low disk loading means efficient, quiet hover; high disk loading means more power and stronger downwash.
Displacement (residue displacement)Sustainability: What happens when a fuel plant takes a waste or residue that someone else was already using: the former user must buy a replacement, often palm or soybean oil, and that replacement carries emissions. Consequential accounting counts this; attributional accounting does not.
Disseminated deposit (disseminated ore)Minerals: A deposit in which ore minerals are scattered as fine grains through the host rock, rather than concentrated in veins. It is usually lower grade but suited to bulk mining.
Dissipative use (dissipative uses)Minerals: A use that spreads a metal so thinly, as in pigments or flame retardants, that recovering it is impractical.
Dissolved oxygen (DO level, dissolved oxygen level)Maritime: The oxygen dissolved in water that fish and other aquatic life breathe, measured in mg/L. Low levels stress or kill stock.
Distillers corn oilSustainability: Oil recovered from the leftovers of corn-ethanol production. It carries none of the ethanol plant's emissions under attributional rules, but it already has a market in animal feed.
Distributed acoustic sensing (DAS, fiber-optic sensing)Maritime: Using a fiber-optic cable as a long chain of vibration sensors by sending laser pulses down it and measuring scattered light.
Distributed control system (DCS)Computing: A plant-wide control system that runs many control loops through controllers spread across a facility, common in chemical and power plants.
Distributed electric propulsion (DEP)Aerospace: Spreading many electric motors and propellers across an airframe. It adds redundancy and can improve lift and efficiency, but multiplies parts and possible failure points.
Distributed maritime operations (DMO)Maritime: A US Navy concept that spreads forces across many dispersed crewed and uncrewed platforms to complicate enemy targeting.
District heatingBatteries: A network of insulated pipes that carries hot water or steam from central plants to heat many buildings. Large heat stores can charge from cheap electricity and feed these networks.
DiversificationFinance: Spreading capital across assets, sectors or regions so that a poor result in one holding has less effect on the whole portfolio. It reduces company-specific risk but cannot remove the risk of the market as a whole.
DividendsFinance: Distributions of a company's profits to its shareholders, paid in cash or additional shares when declared by the board. They are not guaranteed and can be cut or suspended.
Diving support vessel (DSV, dive support vessel)Maritime: A ship equipped with saturation diving systems, cranes and dynamic positioning to support divers and subsea work offshore.
DO-178C (RTCA DO-178C)Aerospace: The standard for developing and verifying airborne software, used by the FAA and EASA. The rigor required scales with how severe a software failure would be.
DO-254 (RTCA DO-254)Aerospace: The standard for designing airborne electronic hardware, such as programmable chips, with rigor scaled to the effect of a failure.
DO-311A (RTCA DO-311A)Aerospace: An RTCA standard for the performance and safety of rechargeable lithium batteries installed in aircraft, including tests that a cell fire stays contained.
DoD Directive 3000.09 (Directive 3000.09)Aerospace: The US Defense Department policy on autonomy in weapon systems, last updated in 2023. It requires designs that allow appropriate levels of human judgment over the use of force and sets senior review before development and fielding.
Dodd-Frank Section 1502 (Section 1502, Form SD, Conflict Minerals Report, Conflict Minerals Rule)Minerals: The 2010 US law requiring SEC-reporting companies to check whether their 3TG comes from the DRC or neighbors and disclose it each year on Form SD.
Dollar-cost averaging (DCA)Finance: Investing a fixed amount on a fixed schedule regardless of price, so more units are bought when prices are low and fewer when they are high. It spreads the timing of purchases and removes the need to pick an entry point; the Portfolio Designer models such a schedule but does not place it.
Domain generalization (domain-generalisation)Computing: A model's ability to perform well on data from settings it was not trained on, such as new scanners, sites or materials.
Doppler shift (Doppler)Aerospace: The change in a signal's frequency when transmitter and receiver move relative to each other. Fast low-orbit satellites cause large shifts that receivers must correct.
Doppler velocity log (DVL)Maritime: A sonar that measures a vessel's speed over the seabed or through the water from the Doppler shift of acoustic echoes, slowing inertial drift underwater.
Double declining balanceFinance: An accelerated depreciation method that applies twice the straight-line rate to the asset's remaining book value each year. An asset with a five-year life is depreciated at 40% of its remaining value annually.
Double-cropping and relay-croppingSustainability: Growing two crops on the same field in one year. In double-cropping the second is planted after the first is harvested; in relay-cropping it is sown into the standing first crop. Both let an oilseed use land that would otherwise sit fallow.
Downwash and outwash (downwash, outwash)Aerospace: Downwash is the air a hovering rotor drives downward; outwash is that air spreading out along the ground. Strong flows can blow debris and knock people over, so vertiport design sets caution areas around the pad.
DRAM (dynamic random-access memory)Computing: Dynamic random-access memory, the main working memory in computers. Each bit is stored as charge on a tiny capacitor that must be refreshed many times per second.
DrawdownFinance: The decline from a prior peak to a subsequent trough, expressed as a percentage of the peak. Maximum drawdown is the largest such decline in a series.
Drift (adit)Minerals: A horizontal underground tunnel used for access, haulage or exploration.
Drive-by-wire (drive by wire)Industry: Controlling a vehicle's steering, braking and throttle electronically instead of by mechanical links, which autonomy systems need.
Drone ship (autonomous spaceport drone ship, landing barge, landing platform vessel)Aerospace: An ocean platform, usually uncrewed, on which a rocket booster lands downrange of the launch site. Landing at sea saves the propellant the booster would need to fly back.
Drop-in fuelSustainability: A renewable fuel chemically similar enough to its fossil counterpart that it can be used in existing engines, tanks and pipelines without modification, and neat (100 percent) rather than blended.
Dry deck shelter (DDS)Maritime: A chamber mounted on a submarine's hull from which divers or vehicles can be launched and recovered while submerged.
Dry roomBatteries: A production room kept at extremely low humidity, because moisture damages lithium-ion and especially sulfide solid-state materials. Running it is a major energy cost.
Dry-electrode process (dry electrode, dry coating)Batteries: Making electrodes from dry powder pressed into film, without a liquid solvent. It removes drying ovens and toxic solvent recovery, but is hard to run at scale.
Dual sourcing (second source, single-source, sole-source)Industry: Buying a critical input from two independent suppliers so one failure does not stop production. Single-sourced parts are a common supply-chain weakness.
Dual-chemistry pack (hybrid pack, mixed-chemistry pack)Batteries: A battery pack that combines two cell chemistries, such as sodium-ion and LFP, so each covers the other's weakness, for example cold-weather power and energy density.
Dual-mode ramjet (DMRJ, dual-mode scramjet)Aerospace: An engine that runs as a ramjet at lower speeds and as a scramjet at higher ones, using the same flow path.
Dual-use (dual-use technology, dual-use goods)Aerospace: Describes goods, software and technology with both civilian and military uses, such as drones, machine tools and some chips. They are controlled under regimes such as the EAR and the Wassenaar Arrangement.
Duration (storage duration)Batteries: How long a storage system can deliver its full rated power: energy rating divided by power rating. Most grid batteries offer 2–4 hours.
Dutch rollAerospace: A coupled side-to-side oscillation in which an aircraft yaws and rolls out of phase, its nose tracing a figure eight. Most aircraft damp it naturally or with yaw dampers; poor damping is a certification issue.
Dynamic positioning (DP)Computing: A computer-controlled system that holds a ship in place using its thrusters, essential during cable repair and offshore work.
Dynamic pressure (max q, max Q)Aerospace: The pressure from a vehicle's motion through air, rising with air density and the square of speed. Rockets throttle down near the point of highest dynamic pressure, called max q, to limit structural loads.
Dysprosium and terbium (dysprosium, terbium, DyFe)Minerals: Heavy rare earths added to NdFeB magnets to keep them strong at high temperatures, as in electric vehicle motors. Supply is concentrated in China and Myanmar.

E

EAR (Export Administration Regulations)Aerospace: The US Commerce Department rules that control exports of commercial and dual-use items, software and technology. Items are classified on the Commerce Control List.
Earnshaw's theoremBatteries: A physics result showing that static magnets alone cannot hold an object in stable levitation. Magnetic bearings therefore need active control, superconductors or a mechanical touchdown bearing.
EASA (European Union Aviation Safety Agency)Aerospace: The EU agency responsible for civil aviation safety, including type certification of aircraft, engines and parts.
EBITDAFinance: Earnings before interest, taxes, depreciation and amortisation, a rough measure of operating earnings before financing and non-cash charges. It is not defined under GAAP and ignores capital spending and working capital needs.
ECCN (export control classification number)Aerospace: A five-character code that places an item on the Commerce Control List, such as 2B001 for certain machine tools. It determines which license requirements apply.
Economic allocationSustainability: Splitting shared emissions in proportion to the market value of each co-product. For soybean it lands close to energy allocation, but it shifts whenever relative prices move.
Edge computing (edge AI, edge analytics)Computing: Processing data near where it is produced, such as on a device or local gateway, instead of in a distant cloud. It cuts delay and bandwidth needs.
Edge placement error (EPE)Computing: The total error in where a feature's edge lands, combining critical dimension, overlay and random variation. It is the budget that ultimately limits patterning.
Effective number of bits (ENOB)Computing: The real precision of an analog or mixed-signal system after noise is counted. Photonic and analog computers often reach only a few effective bits.
Electric-pump-fed engine (electric pump-fed)Aerospace: A rocket engine whose propellant pumps are driven by battery-powered electric motors instead of a turbine. It simplifies small engines, but battery mass rules it out for large ones.
Electrical steel (silicon steel, grain-oriented electrical steel, GOES, non-oriented electrical steel, NOES)Industry: Steel with ≈3% silicon, rolled into thin sheets that cut energy loss in transformer and motor cores. Grain-oriented grades suit transformers; non-oriented grades suit motors.
Electrochemical cell (cell, battery cell, galvanic cell)Batteries: The basic unit of a battery: two electrodes separated by an electrolyte, in which chemical reactions move electrons through an outside circuit. Cells are joined in series to raise voltage and in parallel to raise capacity.
ElectrodeBatteries: A conductor through which current enters or leaves a cell. In batteries it is usually a thin coating of active material on a metal foil.
Electrode coating (slurry coating, wet coating, roll-to-roll)Batteries: Spreading a slurry of active material, binder and solvent onto metal foil and drying it, usually on fast roll-to-roll lines. Coating speed, uniformity and drying energy drive cost.
Electroencephalography (EEG)Computing: Recording the brain's electrical activity with electrodes on the scalp. It is the main signal source for non-invasive brain-computer interfaces.
Electrolysis (electrolytic hydrogen)Sustainability: Splitting water into hydrogen and oxygen with electricity, using about 55 kWh per kilogram of hydrogen. Its footprint is set by the power source.
ElectrolyteBatteries: The medium inside a cell that lets ions move between the electrodes while blocking electrons. Lithium-ion cells normally use a flammable liquid of lithium salt in organic solvents; solid-state cells use a solid.
Electrolyte filling (electrolyte injection)Batteries: Injecting liquid electrolyte into an assembled cell and letting it soak into the electrodes before sealing.
Electromagnetic pulse (EMP)Aerospace: A short, intense burst of electromagnetic energy, from a nuclear detonation or a dedicated device, that can induce damaging currents in electronics.
Electron beam melting (EBM)Industry: A powder bed process that melts metal with an electron beam in a vacuum. It suits reactive and crack-prone alloys.
Electron-beam lithography (e-beam lithography, EBL, direct write, maskless lithography, variable-shaped beam, VSB)Computing: Writing patterns directly with a focused electron beam, without a mask. It is very fine but slow, so it is used mostly to make masks and for research.
Electronic design automation (EDA)Computing: Software used to design, simulate and verify chips, from logic design to physical layout. A few vendors dominate it.
Electronic speed controller (ESC)Aerospace: The circuit that drives an electric motor on a drone, switching current to set its speed on commands from the flight controller.
Electronic warfare (EW)Aerospace: Military use of the electromagnetic spectrum to attack, protect or exploit, including jamming, spoofing and intercepting enemy signals.
Electronic-grade chemicals (wet electronic chemicals, high-purity process chemicals, semiconductor wet chemicals)Industry: Ultra-pure acids, solvents, gases and slurries used in chip manufacturing, with impurities in parts per billion or less. Qualification takes many months and suppliers are concentrated.
Electrorefining (electrolytic refining)Minerals: Purifying a metal by dissolving an impure anode and plating pure metal onto a cathode.
ElectrowinningIndustry: Recovering pure metal from a solution by passing current through it, so the metal plates onto cathodes. It is a final step in many hydrometallurgical plants.
Ellingham diagram (Ellingham ordering)Minerals: A chart of how stable metal oxides are at different temperatures, used to predict which oxides a reducing agent or electrolysis cell will split first.
eLoran (enhanced Loran, Loran-C, Loran, LORAN)Maritime: Enhanced Loran, a modernized low-frequency (90–110 kHz) terrestrial radio navigation and timing system. Its strong ground-based signals are hard to jam, making it a backup for satellite navigation.
Embedding (vector embedding, embedding model)Computing: A list of numbers that represents the meaning of text, images or other data, so that similar items sit close together. Embeddings power semantic search and retrieval.
Embodied emissionsSustainability: Emissions released in making equipment and infrastructure, such as tractors, refineries and pipelines, spread over their useful life.
Emission control (EMCON)Maritime: Deliberately limiting radio, radar and other emissions so a ship, submarine or vehicle is harder to detect.
Emission factorSustainability: A conversion rate that turns an activity into emissions, for example the share of applied nitrogen fertilizer that escapes as N₂O. The IPCC's 2019 update set 1.6 percent for synthetic nitrogen in wet climates and 0.5 percent in dry ones, replacing a single 1 percent.
Emissions (greenhouse gas emissions)Sustainability: Releases of heat-trapping gases, chiefly carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). In lifecycle accounting they are converted into a single CO₂-equivalent figure.
End of life (EOL, T80)Batteries: The point at which a battery is judged no longer fit for its first use, often when capacity falls to 70–80% of new. End-of-life batteries go to second-life use or recycling.
Endothermic fuelAerospace: A jet fuel that absorbs heat by breaking down chemically as it warms, so it can cool engine and airframe parts before it burns. High-Mach vehicles need it because their heat loads exceed what ordinary fuel can absorb.
EnergeticsAerospace: The science and industry of explosives, propellants and pyrotechnics used in munitions and rocket motors. Western supply depends on a small number of plants.
Energy allocation (energy-allocated basis)Sustainability: Splitting shared emissions in proportion to the energy content of each co-product. It is the EU RED's rule. Soybean oil is about 19 percent of crushed mass but about a third of its energy, so energy allocation assigns the oil about 1.8 times the burden of mass allocation.
Energy arbitrage (arbitrage, time-shifting)Batteries: Charging storage when electricity is cheap and discharging when it is expensive, earning the price difference minus losses.
Energy per bit (pJ/bit, fJ/bit, energy per operation)Computing: The energy needed to move or store one bit of data, in picojoules (pJ) or femtojoules (fJ). It is the key efficiency measure for interconnects and memory.
Engine-out capability (engine-out tolerance)Aerospace: The ability of a vehicle with several engines to complete its mission if one engine fails. It needs spare thrust and flight software that can adjust to the loss.
Engineering Brief 105A (EB 105A)Aerospace: FAA guidance for designing vertiports, issued in December 2024. It covers landing area sizes, approach paths, markings, lighting and charging infrastructure; following it is voluntary.
Enhanced-efficiency nitrogen fertilizerSustainability: Fertilizer formulated to release nitrogen slowly or to block the microbial steps that produce N₂O, using coatings or chemical inhibitors. It is a mitigation for soil nitrous oxide.
Entanglement (quantum entanglement)Computing: A quantum link between particles whose measurement results stay correlated however far apart they are. It is a key resource for quantum computing and communication.
Entity List (BIS Entity List)Computing: A US Commerce Department list of foreign companies and organizations that need a license to receive US-controlled items, which is usually denied. Many Chinese chipmakers are on it.
Entry into serviceAerospace: The point at which an aircraft type begins regular commercial operation with a customer, after certification and delivery.
Environmental assessment (EA, tiered environmental assessment)Aerospace: A NEPA review that decides whether a federal action may significantly affect the environment. If not, it ends with a finding of no significant impact; if so, a full environmental impact statement is needed.
Environmental impact statement (EIS)Aerospace: The most detailed NEPA review, required when a federal action may significantly affect the environment. It takes longer and involves more public comment than an environmental assessment.
EPA (U.S. Environmental Protection Agency)Sustainability: The federal agency that runs the Renewable Fuel Standard and its lifecycle analysis, including ILUC.
EquityFinance: The owners' residual claim on a company, equal to total assets minus total liabilities. The term also refers to the shares that represent that ownership.
Equity methodFinance: The way a company accounts for an investment over which it has significant influence, usually a 20% to 50% stake. It records its share of the investee's profit in its own income and adjusts the investment's carrying value, while dividends received reduce that value.
ERCOT (Electric Reliability Council of Texas)Computing: The Electric Reliability Council of Texas, which runs most of the Texas power grid and its wholesale market. The grid is largely isolated from the rest of the US.
Error-correcting code (ECC memory)Computing: Extra data stored with information so that errors can be detected and fixed automatically. Memory and storage rely on it as cells shrink.
Escrowed sharesFinance: Shares held by a neutral third party until stated conditions are met, such as a vesting period ending or a merger closing. Until release they cannot be sold or transferred, which protects the other parties to the deal.
eSTOL (electric short takeoff and landing)Aerospace: An electric aircraft designed to take off and land on very short strips, often using propellers blowing over the wing for extra lift. It trades vertical flight for better range and payload than an eVTOL.
EU AI Act (AI Act, Regulation (EU) 2024/1689, Artificial Intelligence Act)Computing: Regulation (EU) 2024/1689, the EU law regulating AI by risk level. Bans on prohibited practices applied from February 2025 and general-purpose model rules from August 2025; a 2026 amendment moved most high-risk obligations to December 2027 and August 2028.
EU Battery Regulation (Regulation (EU) 2023/1542, Batteries Regulation)Batteries: Regulation (EU) 2023/1542, which replaced the 2006 Battery Directive and covers batteries across their life cycle in the EU. It sets battery passports, carbon footprint rules, recycling targets, recycled content minimums and supply-chain due diligence, now due from August 2027.
EU Chips Act (European Chips Act, Regulation (EU) 2023/1781, Chips Act 2.0)Computing: Regulation (EU) 2023/1781, in force since September 2023, which supports chip research, pilot lines and new fabs and aims for 20% of the global semiconductor market by 2030. A Chips Act 2.0 was proposed in June 2026.
EU Conflict Minerals Regulation (Regulation (EU) 2017/821, EU 2017/821)Minerals: Regulation (EU) 2017/821, which since 1 January 2021 requires EU importers of 3TG above set volumes to carry out supply-chain due diligence.
EuroHPC Joint Undertaking (EuroHPC, AI Factory, AI factories)Computing: The EU body that funds and buys supercomputers, AI factories and quantum computers together with member states. The machines are hosted in national centers.
Eutrophication (dead zone, dead zones, hypoxic zone, algal bloom, harmful algal bloom)Maritime: Excess nutrients, often from farm runoff or fish waste, that feed algal blooms which then decay and strip oxygen from the water, creating dead zones.
EUV light source (laser-produced plasma, LPP, EUV source)Computing: The system that produces 13.5 nm light for EUV scanners, usually by hitting tiny tin droplets with a powerful laser to make glowing plasma. Source power sets scanner throughput.
EUV lithography (EUV, extreme ultraviolet, EUVL)Computing: Lithography using extreme ultraviolet light at 13.5 nm, which needs vacuum and mirrors instead of lenses. It prints the finest features in leading chips; ASML is the only supplier of EUV scanners.
eVTOL (electric vertical takeoff and landing)Aerospace: An electric aircraft that takes off and lands vertically, usually with several battery-powered rotors. eVTOLs are being developed as air taxis, cargo carriers and military vehicles. Battery energy limits their range and payload.
eVTOL Integration Pilot Program (eIPP)Aerospace: A US program created under a June 2025 executive order that pairs state, local and tribal governments with eVTOL and other advanced air mobility companies. Its projects fly early operations and generate data for future FAA rules.
Ex-China price (ex-China, China domestic price, price bifurcation)Minerals: The price of a material sold outside China, which can sit far above China's domestic price when export controls split the market.
Exclusive economic zone (EEZ, EEZs)Minerals: The sea out to 200 nautical miles from a country's coast, where it holds rights over fishing, energy and seabed minerals.
Exothermic reactionSustainability: A chemical reaction that releases heat. Hydrotreating is strongly exothermic, and plants recover that heat to cut their energy use.
Expendable launch vehicle (expendable, ELV)Aerospace: A rocket, or part of one, used for a single flight and not recovered. Flying a reusable booster in expendable mode lifts more payload, because no propellant is held back for landing.
Experimental amateur-built (amateur-built, 51 percent rule)Aerospace: An FAA category for aircraft whose owner built the major portion, at least 51%, for education or recreation. Such aircraft cannot be used commercially.
Exploration and exploitation licences (exploration licence, exploitation licence, exploitation license, mining licence, mining license, concession)Minerals: Government permits that first allow searching for minerals in an area and later allow mining them. In Greenland and many civil-law countries an exploitation licence is the mining permit.
Exploration contract (ISA exploration contract, plan of work, exploitation plan of work)Minerals: An International Seabed Authority contract giving a sponsored contractor exclusive rights to explore a seabed area for a set mineral, usually for 15 years.
Extended producer responsibility (EPR, producer responsibility organization)Batteries: A policy that makes producers pay for collecting and recycling their products at end of life, usually through producer responsibility organizations.
Extractive species (extractive aquaculture, bivalves, filter feeders)Maritime: Farmed organisms, such as seaweed, mussels and oysters, that need no feed because they take nutrients or food particles from the water.
Extremely improbableAerospace: The certification target for catastrophic failure conditions on large aircraft: no more likely than about once per billion flight hours. Regulators apply similar targets to eVTOLs carrying passengers.

F

FAA (Federal Aviation Administration)Aerospace: The US agency that regulates civil aviation and commercial space transportation, including aircraft certification, pilots, airspace and launch licensing.
FAA Office of Commercial Space Transportation (FAA AST)Aerospace: The FAA office that licenses commercial launches and reentries in the US and oversees their public safety.
Fab (fabrication plant, semiconductor fab)Computing: A semiconductor fabrication plant. Leading-edge fabs cost tens of billions of US dollars and take years to build and ramp.
FactorFinance: A measurable characteristic used to rank securities, such as momentum or value. A factor portfolio holds the highly ranked names and, in long-short form, sells the lowly ranked ones.
Fair value through other comprehensive income (FVOCI)Finance: An IFRS 9 classification in which changes in an investment's fair value go to other comprehensive income, a part of equity, rather than to profit or loss. For equity investments held this way, the gains are not moved into profit when the investment is sold.
Fair value through profit or loss (FVTPL)Finance: An IFRS 9 classification in which changes in an investment's fair value are recorded in profit or loss each period. Reported earnings therefore move with the market value of those holdings.
FAME (fatty acid methyl ester, biodiesel)Sustainability: First-generation biodiesel made by reacting fats with methanol. It keeps oxygen in the molecule, which limits its blend share: the European diesel standard EN 590 caps it at 7 percent. It is chemically distinct from HVO.
Fast charging (fast charge, ultra-fast charging)Batteries: Charging a battery much faster than usual, typically at 2C or more, or from 10% to 80% in under ≈20 minutes. It stresses cells through heat and lithium plating.
Fat tailsFinance: A distribution in which extreme outcomes occur more often than a normal (bell curve) distribution predicts. Financial returns are generally fat-tailed, so models that assume normality understate the chance of large moves.
Fault tree analysisAerospace: A top-down method that maps how combinations of component failures could cause a hazard, used to estimate how likely it is.
Fault-tolerant quantum computing (fault tolerance, fault-tolerant)Computing: Quantum computing in which error correction keeps errors under control however long the computation runs. It is the goal for running algorithms such as Shor's.
FCC Covered List (Covered List)Aerospace: A US Federal Communications Commission list of communications equipment and services judged to pose national security risks. Listed equipment cannot get new FCC equipment authorizations, which most radio devices need to be sold in the US. In December 2025 the FCC added foreign-made drones and drone critical components.
FDA approval pathways (IND, Investigational New Drug, NDA, New Drug Application, PMA, premarket approval)Maritime: US routes to market for medical products. An IND lets a drug be tested in people and an NDA seeks its approval. Premarket approval is the strictest route for high-risk devices.
Feasibility study (DFS, definitive feasibility study, bankable feasibility study)Minerals: The most detailed engineering and economic study of a mine before a construction decision, used to raise project finance. Bankable or definitive versions carry the tightest cost estimates.
Feed conversion ratio (FCR)Maritime: The kilograms of feed needed to add one kilogram of animal weight. Lower ratios mean more efficient farming; farmed salmon is typically ≈1.1–1.3.
Feeder link (gateway link)Aerospace: The radio link between a satellite or high-altitude platform and a ground gateway that connects it to the internet or a core network. Users connect on separate service links.
Ferrite magnet (ferrite, ceramic magnet, hard ferrite)Minerals: A cheap, rare-earth-free ceramic magnet made of iron oxide with strontium or barium. It is far weaker than NdFeB but widely used.
Ferrosilicon (FeSi, FeSi75)Industry: An alloy of iron and silicon, made in electric furnaces, used to remove oxygen from steel, to treat cast iron and to make magnesium. Grades are named by silicon content, such as FeSi75.
FFC Cambridge process (FFC-Cambridge, electro-deoxidation)Minerals: A method that removes oxygen from a solid metal oxide by electrolysis in molten calcium chloride at ≈900–950 °C, producing metal powder and oxygen.
Fiber-optic guided drone (fiber-optic drone)Aerospace: A drone controlled through a thin optical fiber that unspools behind it, instead of by radio. It cannot be jammed, but the spool limits its range.
Field-reversed configuration (FRC)Industry: A compact fusion approach in which plasma currents create their own closed magnetic field, needing simpler external magnets than a tokamak.
Figure of merit (FoM, hover efficiency)Aerospace: A rotor's hover efficiency: the ratio of the ideal power predicted by momentum theory to the power actually needed. Good helicopter rotors reach ≈0.7–0.8.
Final approach and takeoff area (FATO)Aerospace: The area around the landing pad over which an aircraft completes its approach to a hover or landing and begins takeoff. In FAA vertiport guidance it is at least twice the rotor diameter across.
Finding of no significant impact (FONSI, mitigated FONSI)Aerospace: A NEPA decision that an action will not significantly affect the environment, sometimes on condition of mitigation measures, so no full impact statement is required.
FinFET (fin field-effect transistor)Computing: A transistor in which the channel is a thin vertical fin wrapped by the gate on three sides, giving better control than flat transistors. It has been standard since the 22 nm–16 nm era and is giving way to gate-all-around designs.
Finite-difference time-domain (FDTD)Aerospace: A computer method for simulating how electromagnetic waves travel and interact with objects, by stepping Maxwell's equations through space and time.
Firm-fixed-price contract (firm fixed price, FFP)Aerospace: A contract with a set price the contractor receives regardless of its actual costs. The contractor keeps any savings but absorbs overruns, which can cause large losses on development work.
First-of-a-kind and nth-of-a-kind (FOAK, NOAK, first-of-a-kind, nth-of-a-kind)Industry: The first unit of a new plant design is usually far costlier than later units, which benefit from learning and standardization. Cost estimates are often stated for the nth unit.
Fishmeal (fish meal)Maritime: Dried, ground fish used as a high-protein ingredient in aquaculture and livestock feed, made mostly from small wild-caught fish.
Fission surface powerAerospace: A small nuclear reactor designed to power a base on the Moon or Mars, including through the ≈14-day lunar night when solar power is unavailable.
Five-axis machining (5-axis machining, multi-axis machining, machining center, mill-turn)Industry: CNC machining in which the tool or part can move along five axes at once, letting complex shapes be cut in one setup. Aerospace and medical parts rely on it.
Fixed seabed arrays (SOSUS, Sound Surveillance System, seabed sensor network)Maritime: Networks of hydrophones laid on the seafloor to monitor ship and submarine traffic, such as the US Cold War SOSUS system.
Fixed-base operator (FBO)Aerospace: A business at an airport that serves private and charter aircraft with fuel, parking, hangars and passenger lounges. Such sites are early candidates for eVTOL operations.
Flight controllerAerospace: The onboard computer that keeps a drone stable and follows commands or a flight plan, using data from its sensors.
Flight envelope (envelope expansion)Aerospace: The range of speeds, altitudes and loads within which an aircraft can fly safely. Flight testing expands the envelope step by step until it covers what certification requires.
Floating farm (floating greenhouse, floating agriculture, farmship, maritime agriculture)Maritime: A farm built on a floating platform or converted ship, growing crops, fish or livestock at sea or in harbors to free land and fresh water.
Flow battery (redox flow battery, vanadium flow battery, vanadium redox flow battery, VRFB, zinc-bromine flow battery)Batteries: A battery that stores energy in liquid electrolytes held in external tanks and pumped through a cell stack. Energy and power can be sized separately, which suits long-duration grid storage, but energy density is low.
Flow-through system (flow-through aquaculture)Maritime: A fish farm that continuously draws in fresh water and discharges it after one pass.
Fluid catalytic cracking (FCC, RFCC, residue fluid catalytic cracking, catalytic cracker)Industry: A refinery process that breaks heavy oil into gasoline and lighter products over a hot powdered catalyst, which is continuously burned clean in a regenerator. Residue versions crack the heaviest fractions.
Fluorspar (fluorite, CaF₂, acidspar, acid-grade fluorspar)Minerals: The mineral fluorite (calcium fluoride, CaF₂), the main source of fluorine for hydrofluoric acid, refrigerants and aluminum smelting. Acid grade is ≥97% CaF₂.
Fly-by-wireAerospace: A flight-control system in which pilot inputs go to computers that move the control surfaces, instead of through cables or rods. It allows stability augmentation and is essential for aircraft that are unstable or hard to fly by hand.
Flywheel energy storage (FESS, flywheel)Batteries: Storing energy in a spinning rotor and recovering it with a motor-generator. Flywheels respond almost instantly and last for many cycles, but lose energy within hours, so they suit short bursts.
Fog computing (fog layer)Computing: A layer of computing between devices and the cloud, using local gateways and servers to filter, process and store data. It suits remote sites with weak connectivity.
Food and feed crop capSustainability: The RED limit on biofuels from food and feed crops: the lower of 7 percent of transport energy or each member state's 2020 share plus 1 percentage point.
Foregone sequestrationSustainability: The carbon that land would have absorbed if it had been left to regrow naturally instead of being farmed for fuel. No regulatory framework charges for it, although CORSIA treats it as a sensitivity case.
Foreign direct product rule (FDPR)Aerospace: An EAR provision that extends US export controls to foreign-made items produced with certain US technology, software or equipment.
Foreign entity of concern (FEOC)Batteries: A US legal category for companies tied to China, Russia, Iran or North Korea, used to bar them from clean-energy tax credits. The 2025 OBBBA law added broader prohibited foreign entity rules for most remaining credits.
Foreign military sales (FMS)Aerospace: The US government program for selling defense equipment and services to allied governments, with the Defense Department managing the purchase on the buyer's behalf.
Formation and aging (formation, cell formation, degassing)Batteries: The first controlled charge cycles of a new cell, which build its protective SEI layer, followed by storage to screen out defective cells and, for pouch cells, degassing. It can take days and is a large share of factory floor space and energy.
Fossil diesel (petroleum diesel)Sustainability: Diesel refined from crude oil. In lifecycle accounting it is the reference fuel that HVO displaces, represented by a single comparator value.
Fossil fuel comparator (fossil baseline)Sustainability: The fixed emissions value for the fossil fuel being replaced, against which savings are measured. The EU RED uses 94 g CO₂e/MJ for transport fuels; the 2009 RED used 83.8 g, CORSIA uses 89 g for jet fuel, and the RED uses 183 g per megajoule of electricity for power generation.
Foundry (contract chipmaker, pure-play foundry)Computing: A company that manufactures chips designed by other companies. The model lets designers avoid owning fabs.
Four coincident peak (4CP)Computing: A Texas transmission charge based on a customer's demand during the single highest 15-minute grid peak of each month from June to September. Large users cut load at expected peaks to lower the charge.
FPGA (field-programmable gate array, FPGAs)Computing: Field-programmable gate array, a chip whose logic can be reconfigured after manufacture. It is used for prototyping, signal processing and low-volume specialized tasks.
FPV drone (first-person view, FPV)Aerospace: A small drone flown by a pilot wearing goggles that show its live camera view, as if sitting on board. Cheap FPV drones carrying explosives have become a mass weapon in the war in Ukraine.
Free cash flowFinance: Cash generated by operations minus capital expenditures. It is the cash left over that can repay debt, pay dividends, buy back shares or be reinvested.
Free cash flow yieldFinance: Trailing twelve-month free cash flow divided by market capitalisation.
Free cooling (seawater cooling)Computing: Cooling a data center with cold outside air or water instead of mechanical chillers, saving energy.
Free fatty acids (FFA)Sustainability: Fatty-acid chains that have broken free of their glycerol backbone, common in degraded oils such as used cooking oil and PFAD. High FFA content makes FAME production harder but suits hydroprocessing.
Free on board (FOB, FOB China)Minerals: A trade term in which the seller delivers goods onto the ship at the export port and the buyer pays freight and insurance from there.
Free-electron laser (FEL, EUV-FEL)Computing: A laser that makes light from a beam of fast electrons in a magnetic field. It could in future supply EUV light for many scanners at once.
Free-space path lossAerospace: The weakening of a radio signal as it spreads out over distance, growing with distance and frequency. It is the largest loss in most satellite links.
Frequency comb (microcomb, optical frequency comb)Computing: A light source that emits many evenly spaced wavelengths at once. Chip-scale microcombs could supply many data channels from one laser.
Frequency regulation (frequency response, frequency containment)Batteries: Fast adjustments to power output that keep grid frequency at its target, 50 Hz or 60 Hz. Batteries and flywheels respond in milliseconds, which suits this service.
Frequency selective surface (FSS)Aerospace: A patterned surface that passes some radio frequencies and blocks others. It is used in radomes and reflectors to shield sensors from unwanted bands.
Frontier model (frontier AI)Computing: One of the most capable AI models available at a given time, usually from a small number of labs with the largest compute budgets.
Froth flotation (flotation, flotation circuit, cleaner circuit, scavenger circuit, depressant)Minerals: Separating minerals by making the target grains repel water so they cling to air bubbles and float off as froth. Collectors, frothers and depressants control which minerals float.
Fuel pathwaySustainability: A specific combination of feedstock, origin, process and energy inputs that regulators certify with its own carbon intensity, for example "U.S. soybean oil to renewable diesel with grid power and grey hydrogen."
Fuel sulfur limit (Euro V fuel, low-sulfur fuel, ppm sulfur)Industry: The maximum sulfur content allowed in fuel, in parts per million. Euro V specification diesel and gasoline are limited to 10 ppm.
Full-flow staged combustion (FFSC)Aerospace: A staged-combustion cycle with two preburners, one fuel-rich and one oxygen-rich, so all propellant passes through the turbines. It allows very high chamber pressure with cooler turbines, at the cost of complexity.
Function and reliability testing (F&R testing, function-and-reliability testing)Aerospace: Flight testing before type certification that shows an aircraft and its systems work reliably in service-like use. US rules set a minimum number of flight hours, commonly 150.
Functional safety (IEC 61508, ISO 26262)Industry: Engineering a system so that its controls respond safely to faults, following standards such as IEC 61508 and, for vehicles, ISO 26262.
Fusion energy (nuclear fusion, fusion power, deuterium-tritium fusion, D-T fusion)Industry: Energy released when light nuclei, such as deuterium and tritium, combine at temperatures of over 100 million °C. It would produce little long-lived waste; commercial fusion power plants are still under development.
Fusion gain (scientific breakeven, Q > 1)Industry: The ratio of fusion power produced to the heating power put into the plasma, written Q. Q above 1 means more fusion energy out than heat in; a power plant needs far more to cover all losses.

G

g CO₂e/kWhSustainability: Grams of CO₂-equivalent per kilowatt-hour of electricity generated. It is the natural unit for backup generators and power plants.
g CO₂e/MJSustainability: Grams of CO₂-equivalent emitted per megajoule of fuel energy. It is the standard unit for comparing fuels because it normalizes for energy content rather than volume or weight.
G-induced loss of consciousness (G-LOC, GLOC, +Gz)Maritime: Blackout caused by sustained head-to-foot acceleration that drains blood from the brain, a hazard for fighter pilots.
g-load (g-force)Aerospace: The acceleration a vehicle and its occupants feel, in multiples of standard gravity. In a 9 g turn everything weighs nine times its normal weight.
GAAP (Generally Accepted Accounting Principles)Finance: The accounting standards set by the Financial Accounting Standards Board that US companies use to prepare financial statements. They make reported results comparable across companies and periods.
Gallium and germanium (gallium, germanium)Minerals: By-product metals used in chips, optics and solar cells. Gallium comes mostly from alumina refining and germanium from zinc refining and coal ash.
Galvanic corrosion (bimetallic corrosion)Maritime: Accelerated corrosion that occurs when two different metals touch in seawater, which acts as an electrolyte.
Gangue (gangue minerals, waste rock)Minerals: The worthless minerals mixed with ore minerals in rock, which processing separates and discards as tailings.
Gas atomization (VIGA, EIGA, powder atomization, plasma atomization)Industry: Making spherical metal powder by blasting a stream of molten metal with high-pressure gas. Vacuum and electrode induction melting variants keep reactive metals clean.
Gas-generator cycle (gas generator cycle)Aerospace: A rocket engine cycle that burns a small share of propellant to drive the turbopumps and dumps that exhaust overboard. It is simpler than staged combustion but wastes some propellant, lowering efficiency.
Gate fidelity (fidelity, two-qubit gate fidelity, gate error)Computing: How closely a quantum operation matches the ideal, as a percentage; the error rate is one minus fidelity. Two-qubit gate fidelity is the most watched hardware benchmark.
Gate-model quantum computer (gate-based quantum computing, universal quantum computer)Computing: A universal quantum computer that runs algorithms as sequences of quantum gates. It can in principle run any quantum algorithm, unlike an annealer.
Gauge repeatability and reproducibility (gauge R&R, GR&R)Industry: A study of how much of measured variation comes from the measuring system itself, by repeating measurements with different operators and parts.
GB 38031 (GB 38031-2025)Batteries: China's mandatory safety standard for electric-vehicle traction batteries. Its 2025 edition, in force from 1 July 2026, requires that a single cell's thermal runaway cause no fire or explosion of the pack.
GDPR (General Data Protection Regulation)Computing: The EU General Data Protection Regulation, which governs how personal data is collected, used and transferred. It includes a right to erasure and limits on transfers outside the EU.
General-purpose AI model (GPAI, GPAI model)Computing: Under the EU AI Act, a model trained on broad data that can perform many tasks, such as a large language model. Its providers face transparency and copyright duties from August 2025.
Generation IV reactors (Gen IV, advanced reactor, advanced reactors)Industry: Advanced reactor designs that use coolants other than water, such as gas, liquid sodium, lead or molten salt, aiming for higher temperatures, better fuel use and passive safety.
Geophysical navigation (gravity-map matching, magnetic anomaly navigation, MagNav, terrain-referenced navigation, TRN, geophysical aiding, map-matching navigation)Maritime: Fixing position by matching measured gravity, magnetic field or seafloor terrain against stored maps, without satellite signals.
Geostationary orbit (GEO, geostationary)Aerospace: A circular orbit 35,786 km above the equator in which a satellite circles once a day and appears fixed in the sky. Three satellites can cover most of the globe, but the distance adds ≈0.24 s of delay each way between two ground points.
Geostationary transfer orbit (GTO)Aerospace: An elongated orbit that rockets use to deliver satellites toward geostationary orbit; the satellite then raises its own low point to reach the final circular orbit. Payload to it is a standard rocket performance figure.
GHG quota (Germany)Sustainability: Germany's greenhouse-gas reduction quota for fuel suppliers, which requires a set percentage cut in the emissions of fuel sold. Germany has not counted palm-based fuels toward it since 2023.
GHG saving (percentage saving)Sustainability: The reduction a fuel achieves against the fossil comparator: comparator minus pathway intensity, divided by the comparator. At 94 g, a fuel of 14 g saves 85 percent.
Gigafactory (giga-factory, gigascale)Batteries: A battery cell factory with annual output measured in gigawatt-hours (GWh). Capacity is quoted in GWh per year; one GWh is enough for ≈15,000 electric cars with ≈65 kWh packs.
Global warming potential (GWP)Sustainability: A factor that expresses how much heat a gas traps over a set period relative to CO₂. GWP100 uses a 100-year window and is the regulatory norm; GWP20 uses 20 years and weights short-lived methane much more heavily.
GLOBIOM (Global Biosphere Management Model)Sustainability: An economic model of global agriculture, forestry and bioenergy land use developed by IIASA in Austria. It tends to produce high ILUC values for vegetable oils because it models strong substitution toward palm, including palm expansion onto peat. Its analysis for the European Commission gave 231 g CO₂e/MJ for palm, 150 g for soybean and 65 g for rapeseed over 20 years.
Glycerol (glycerine)Sustainability: The three-carbon backbone released when triglycerides are split. It is a co-product of FAME biodiesel, not of HVO.
GNSS (global navigation satellite system, satellite navigation)Aerospace: The general term for satellite navigation systems, including GPS, Galileo, GLONASS and BeiDou. Receivers compute position from the timing of signals from several satellites.
GNSS-denied navigation (GPS-denied navigation, visual-inertial navigation)Aerospace: Navigating when satellite positioning is jammed, spoofed or unavailable, using inertial sensors, cameras, terrain matching or other references instead.
Golden Dome (Golden Dome for America, Iron Dome for America)Aerospace: A US homeland missile-defense initiative launched by executive order in January 2025, first titled Iron Dome for America and renamed the next month. It aims to defend against ballistic, hypersonic and cruise missiles, including with space-based sensors and interceptors.
GPU (graphics processing unit, GPUs)Computing: Graphics processing unit, a processor with thousands of small cores that run the same operation in parallel. Originally for graphics, it is now the main chip for AI training and inference.
Grain boundary diffusion (GBD, grain-boundary diffusion)Minerals: Applying dysprosium or terbium to a finished magnet's surface and heating it so they spread along grain edges. It raises heat resistance with far less heavy rare earth.
Grams per tonne (g/t)Minerals: The usual grade unit for gold and platinum group metal ores. One g/t equals one part per million.
Graphite anode (natural graphite, synthetic graphite, spherical graphite)Batteries: The standard lithium-ion anode, made of natural graphite mined and purified, or synthetic graphite made by heating petroleum coke or pitch to ≈3,000 °C. China dominates both supply chains.
Grapnel (grapnels, grappling hook)Maritime: A hooked tool dragged along the seabed from a cable ship to catch and lift a submarine cable for repair.
Gravimeter (gravity gradiometer, quantum gravimeter)Maritime: An instrument that measures local gravitational acceleration. Mobile gravimeters enable gravity-map navigation and subsurface surveys.
Gravity separation (gravity concentration, dense media separation)Minerals: Separating minerals by density using jigs, spirals or shaking tables, common for tin, tungsten, tantalum and gold.
Green hydrogen (renewable electrolytic hydrogen)Sustainability: Hydrogen made by electrolysis powered by renewable electricity such as wind or solar. Dedicated wind power gives about 1 kg CO₂e per kg of hydrogen. Hydrogen from nuclear-powered electrolysis is sometimes called pink hydrogen.
Greenfield and brownfield projects (greenfield, brownfield)Minerals: A greenfield mine is built on an undeveloped site; a brownfield project expands or restarts an existing operation, usually with lower risk and cost.
Greenland Uranium Act (Act No. 20 of 2021, Uranium Act, Greenland uranium ban)Minerals: Greenland's Act No. 20 of 2021, which bans prospecting, exploring for and mining uranium, including ores with more than 100 ppm uranium. It blocks some uranium-bearing rare earth deposits.
GREET (Greenhouse gases, Regulated Emissions, and Energy use in Technologies)Sustainability: Argonne's lifecycle model for fuels and vehicles, the reference tool for U.S. fuel carbon accounting. R&D GREET is the research version; CA-GREET and 45ZCF-GREET are regulatory adaptations.
GreisenMinerals: Granite altered by hot fluids into quartz and mica, which can host tin and tungsten ores.
Grey hydrogenSustainability: Hydrogen made from natural gas, usually by steam methane reforming, with the CO₂ vented to the atmosphere. It is the default at most refineries. It emits about 10 to 14 kg CO₂e per kg of hydrogen.
Gross profitFinance: Revenue minus the cost of goods sold. It shows how much a company earns from making and selling its products before overhead.
Gross refining margin (GRM, refining margin)Industry: The value of a refinery's products minus the cost of its crude, per barrel, before operating costs.
Gross tonnage (GT)Maritime: A measure of a ship's total enclosed internal volume, used to set port dues, crewing rules and safety requirements. Despite the name, it is not a weight.
Ground control station (GCS)Aerospace: The equipment an operator uses to fly a drone and receive its data, from a handheld controller to a trailer of consoles.
Ground station (ground segment)Aerospace: A site with antennas and equipment that communicates with satellites. The ground segment as a whole also includes networks, control centers and software.
Ground support equipment (GSE)Aerospace: The equipment on the ground that prepares, fuels, powers and launches a vehicle, such as propellant lines, umbilical connections, transporters and launch mounts.
Groundwave (ground wave)Maritime: A radio signal that travels along the Earth's surface rather than in a straight line, letting low-frequency signals such as eLoran reach far beyond the horizon.
Grover's algorithm (Grover)Computing: A quantum search algorithm that finds an item among N options in about √N steps instead of N. It weakens, but does not break, symmetric encryption.
GTAP-BIOSustainability: A version of the Global Trade Analysis Project model from Purdue University, extended to represent biofuels and land use. It is a computable general equilibrium model that simulates how the whole world economy adjusts to extra fuel demand. CARB's GTAP-BIO values are 71.4 g CO₂e/MJ for palm, 29.1 g for soybean and 14.5 g for canola, at the low end of published ILUC estimates.
Gyroscope types (ring laser gyroscope, RLG, fiber-optic gyroscope, FOG, Sagnac effect)Maritime: Rotation sensors used in navigation: ring laser and fiber-optic gyroscopes use light and the Sagnac effect; cold-atom gyroscopes use atom interferometry.
Gyroscopic precessionAerospace: The effect by which a force applied to a spinning rotor takes effect 90° later in its rotation. Rotor designers must account for it, and some aircraft use it deliberately for control.
Gyrostabilizer (gyroscopic stabilizer, gyro stabilizer)Maritime: A spinning flywheel mounted in a vessel to resist rolling in waves.

H

Haber-Bosch process (Haber–Bosch)Industry: The industrial process that makes ammonia from nitrogen and hydrogen over an iron catalyst at high temperature and pressure. It underpins most of the world's nitrogen fertilizer.
HafniumMinerals: A metal always found with zirconium and separated during nuclear-grade zirconium production. It is used in superalloys, chip insulators and reactor control rods.
Half-pitch (metal pitch)Computing: Half the distance from one line to the next in a repeating pattern, the standard measure of lithographic resolution.
Halide electrolyte (halide solid electrolyte)Batteries: A solid electrolyte based on lithium metal chlorides or other halides. It combines good conductivity with stability at high voltage, but is still at an early stage.
Hall-Héroult process (Hall–Héroult, aluminum smelting, aluminium smelting)Industry: The standard method for making aluminum: alumina is dissolved in molten cryolite at ≈950 °C and split by electric current, with carbon anodes that burn and release CO₂.
HallucinationComputing: When an AI model states something false or invented as if it were fact, such as a fake citation. Retrieval and verification steps aim to reduce it.
Halving (bitcoin halving, block subsidy, block reward)Computing: The scheduled cut in half of bitcoin's block reward, about every four years. The April 2024 halving reduced it to 3.125 BTC per block.
HandoverAerospace: Passing a user's connection from one cell, beam or satellite to another as either side moves. Low Earth orbit satellites move fast, so handovers happen every few minutes.
HAPS (high-altitude platform station, high-altitude platform system, high-altitude pseudo-satellite)Aerospace: An aircraft, airship or balloon that holds position in the stratosphere, ≈20 km up, to provide communications, sensing or navigation over a region. The ITU defines high-altitude platform stations as operating at 20–50 km. Solar power and weather limit their payload and endurance.
Hard carbonBatteries: A disordered form of carbon, made by heating biomass, resins or coal, that serves as the standard sodium-ion anode. Graphite does not hold sodium well, so hard carbon supply is a key sodium-ion bottleneck.
Hard disk drive (HDD, HAMR, heat-assisted magnetic recording)Computing: A storage drive that records data magnetically on spinning platters. It remains the cheapest storage per terabyte for large, less active data.
Hash rate (hashrate, EH/s, J/TH, TH/s)Computing: The computing power devoted to bitcoin mining, in hashes per second; network totals are in exahashes per second (EH/s). Machine efficiency is measured in joules per terahash (J/TH).
Head-on gutted (HOG, HOG weight)Maritime: A trade form of fish with the guts removed but the head left on, the standard weight basis for salmon production and prices.
Heat as a Service (HaaS)Batteries: A business model in which a provider owns and runs a heating system and sells the customer heat at an agreed price, instead of selling the equipment.
Heat pumpBatteries: A device that moves heat from a cooler place to a warmer one using electricity, delivering several units of heat for each unit of power used.
Heat-pipe reactor (heat pipe reactor)Industry: A microreactor that moves heat from the core with sealed heat pipes instead of pumped coolant, reducing moving parts.
Heat-to-heat and power-to-power efficiency (heat-to-heat efficiency, power-to-power efficiency, electric-to-electric efficiency)Batteries: Heat-to-heat efficiency counts heat delivered against energy put in; power-to-power counts electricity returned. Thermal stores score highly on the first but far lower on the second, a common source of confusion.
Heavy mineral sands (mineral sands)Minerals: Beach and dune sands rich in dense minerals such as ilmenite, rutile, zircon and monazite, mined for titanium, zirconium and rare earths.
HEFA (hydroprocessed esters and fatty acids)Sustainability: The technical name for the hydroprocessing route that turns fats and oils into paraffinic fuels. It produces both HVO for road use and most of today's sustainable aviation fuel.
Helium (liquid helium)Industry: An inert gas recovered mainly as a byproduct of natural gas processing and liquefaction. Liquid helium, at ≈4 K, cools MRI and research magnets; the gas is vital for chipmaking, fiber drawing and leak testing.
Helium-3 (He-3, ³He, helium 3)Minerals: A light, stable helium isotope implanted in lunar soil by the solar wind at parts-per-billion levels. It is sought for cryogenic cooling and proposed fusion fuel.
HIBS (HAPS as IMT base stations)Aerospace: A high-altitude platform acting as a mobile-network base station that serves ordinary phones. WRC-23 identified bands for it worldwide at 694–960 MHz, 1,710–1,885 MHz and 2,500–2,690 MHz, with conditions to protect existing services.
High ILUC-risk biofuelSustainability: An EU category for crop-based fuels whose expansion has significantly moved into high-carbon land, identified in a 2019 delegated regulation that limited the category to palm oil. Their counting toward targets is to be phased out by 2030.
High-bandwidth memory (HBM, HBM3E, HBM4)Computing: DRAM dies stacked vertically and placed beside a processor on an interposer, giving very high bandwidth. It is essential for AI accelerators.
High-enthalpy test facility (high-enthalpy ground testing, shock tunnel, arc jet)Aerospace: A ground facility, such as a shock tunnel or arc jet, that reproduces the extreme heat and flow conditions of hypersonic flight. Test runs last seconds or less, so flight tests are still needed.
High-mix, low-volume production (high-mix/low-volume, HMLV, small-batch production)Industry: Making many different products in small batches. It favors flexible machines and skilled staff and is the hardest setting to automate fully.
High-NA EUV (High-NA, 0.55 NA, Hyper-NA)Computing: EUV scanners with a numerical aperture of 0.55 instead of 0.33, which print finer features in one exposure. They use anamorphic optics and expose half the field size, so large chips are stitched.
High-nickel cathode (high-nickel, nickel-rich cathode)Batteries: A nickel-based cathode with roughly 80% or more nickel among its metals, such as NMC811 or NCA. It raises energy density and cuts cobalt use, but is harder to make and less stable.
High-oleic soybean oilSustainability: Soybean oil bred to contain more monounsaturated fat and fewer double bonds. It needs less hydrogen to process, which lowers HVO emissions by about 1 g CO₂e/MJ.
High-performance computing (HPC, supercomputing, supercomputer)Computing: Using supercomputers or clusters of many processors working in parallel to solve large scientific and engineering problems.
High-power microwave (HPM)Aerospace: A weapon that emits intense bursts of microwave energy to disrupt or burn out electronics. It can disable many drones at once.
High-pressure acid leaching (HPAL, mixed hydroxide precipitate, MHP)Minerals: Dissolving nickel and cobalt from laterite ore with sulfuric acid at high temperature and pressure. It yields intermediates such as mixed hydroxide precipitate for battery materials.
High-pressure nervous syndrome (HPNS)Maritime: Tremors, dizziness, nausea and impaired thinking caused by pressure itself on the nervous system, appearing in deep helium dives below ≈150 msw.
High-temperature electrolysisSustainability: Electrolysis run at several hundred degrees using solid-oxide cells, which needs less electricity per kilogram because part of the energy comes as heat, for example from a neighboring process.
High-temperature gas-cooled reactor (HTGR, pebble-bed reactor, HTR)Industry: A reactor cooled by helium and moderated by graphite, with outlet temperatures high enough for industrial heat. Pebble-bed designs use fuel in tennis-ball-sized spheres.
High-throughput satellite (HTS)Aerospace: A communications satellite that reuses frequencies across many narrow spot beams, giving far more total capacity than older wide-beam designs.
High-volume manufacturing (HVM)Computing: Full-scale production of a chip or process, after development and pilot stages.
High-water markFinance: The highest value an account or fund has reached. A drawdown from the high-water mark is the decline from that peak, which can occur while the account is still above the money originally put in.
HIPAA (Health Insurance Portability and Accountability Act, protected health information, PHI)Computing: The US Health Insurance Portability and Accountability Act, which protects patient health information and governs how healthcare providers and their vendors handle it.
Hit rateFinance: The share of closed positions that were exited above their entry price. Hit rate says nothing about the size of wins and losses.
HNSW (hierarchical navigable small world)Computing: Hierarchical navigable small world, a graph-based index for approximate nearest neighbor search. It is fast and accurate but memory-hungry.
Horizontal transportIndustry: Moving containers between quay cranes and the yard, by terminal tractors, straddle carriers or automated guided vehicles.
Host rock (host mineral)Minerals: The rock that surrounds or contains a mineral deposit. Its size says nothing about how much metal the deposit holds.
Hot-fire and static-fire tests (hot-fire test, hot fire, static-fire test, static fire)Aerospace: Ground tests that fire rocket engines while the hardware is held down. A hot-fire usually tests an engine or stage on a test stand; a static fire tests the fully assembled vehicle on its launch pad before flight.
Hotel load (hotel loads, house load)Maritime: Electricity a vessel uses for everything other than propulsion, such as lighting, climate control, galley, navigation and computing.
Human Landing System (HLS)Aerospace: NASA's program buying commercial landers to carry astronauts between lunar orbit and the Moon's surface for Artemis missions.
Human-in-the-loop and human-on-the-loop (human-in-the-loop, human-on-the-loop)Aerospace: Two levels of human control over autonomous weapons. In the loop, a person must approve each engagement; on the loop, the system acts on its own while a person monitors and can intervene.
HVO (hydrotreated vegetable oil, renewable diesel)Sustainability: A paraffinic diesel made by reacting vegetable oils, waste oils or animal fats with hydrogen. It is chemically almost identical to the hydrocarbons in fossil diesel, contains no oxygen and can be used neat. In the United States it is usually called renewable diesel.
Hybrid additive-subtractive machine (hybrid manufacturing)Industry: A machine that both deposits material and machines it, so a part can be built and finished in one setup.
Hybrid bondingComputing: Joining chips or wafers face to face with direct copper-to-copper and oxide bonds, without solder bumps. It allows much denser connections for stacked memory and logic.
Hybrid quantum-classical computing (hybrid quantum-classical)Computing: Running workloads that split tasks between quantum processors and classical computers, often in supercomputing centers. The integration software and scheduling are major challenges.
Hydrodeoxygenation (HDO)Sustainability: The reaction route that removes oxygen from fats as water by adding hydrogen. It keeps every carbon atom, maximizing yield, but consumes the most hydrogen.
Hydrogen reduction of ilmenite (ilmenite reduction)Minerals: Heating ilmenite with hydrogen so it gives up oxygen as water, which is then split to make oxygen. It is one of the simplest lunar oxygen routes.
Hydrokinetic turbine (tidal stream turbine, hydrokinetic generator, marine current turbine)Maritime: A turbine that generates electricity from moving water, such as tidal or river currents, without a dam.
Hydrolox (LOX/LH2)Aerospace: Rocket propellant made of liquid hydrogen and liquid oxygen. It gives the highest specific impulse of common propellants, but hydrogen is bulky and must be kept at ≈20 K, so tanks are large and leaks are frequent.
Hydrometallurgy (hydrometallurgical recycling, hydromet)Batteries: Recovering metals by dissolving them in acid and separating them chemically. It recovers lithium as well as nickel and cobalt at high purity and is now the dominant recycling route.
Hydrophone (hydrophones, hydrophone array)Maritime: An underwater microphone that converts sound pressure into an electrical signal. Arrays of hydrophones can tell the direction of a sound.
Hydroponics (nutrient film technique, NFT, deep-water culture, DWC, aeroponics)Maritime: Growing plants without soil, with roots in a nutrient solution. Nutrient film technique and deep-water culture are common methods; aeroponics mists the roots instead.
Hydroprocessing (hydrotreating)Sustainability: Refining a feedstock by reacting it with hydrogen at high temperature and pressure over a catalyst. For HVO it saturates double bonds and removes oxygen, turning oil into hydrocarbons.
Hydrothermal vein (quartz vein, vein deposit, hydrothermal deposit)Minerals: A crack in rock filled with minerals deposited by hot water, often quartz carrying gold, antimony or tungsten.
Hydrotreating catalystSustainability: The metal compounds that make hydroprocessing work, typically sulfided nickel-molybdenum (NiMo) or cobalt-molybdenum (CoMo). They are replaced every few years and usually recycled for their metals.
HygienisationSustainability: Heat treatment that sterilizes animal by-products to destroy pathogens and prions before further use. For Category 1 and 2 material the EU standard is pressure sterilization at 133 °C and 3 bar for 20 minutes. The RED's animal-fat values exclude hygienisation emissions.
Hyperbaric chamber (decompression chamber, recompression chamber, hyperbaric oxygen therapy)Maritime: A sealed chamber pressurized above atmospheric pressure, used for saturation diving, decompression and medical treatment.
Hyperscaler (hyperscale)Computing: One of the largest cloud companies that run vast data center fleets, such as Amazon, Microsoft and Google.
Hypersonic (hypersonics, hypersonic flight)Aerospace: Flight at roughly Mach 5 and above. At these speeds heating, air chemistry and shock waves dominate vehicle design, and materials must survive extreme temperatures.

I

IAEA (International Atomic Energy Agency)Industry: The International Atomic Energy Agency, the UN body that sets nuclear safety standards and verifies that nuclear material is not diverted to weapons.
ICAO (International Civil Aviation Organization)Sustainability: The United Nations agency for international civil aviation, based in Montreal. It runs CORSIA and publishes its default lifecycle values.
ICCT (International Council on Clean Transportation)Sustainability: An independent nonprofit research organization that analyzes transport emissions for policymakers.
IDIQ (indefinite delivery, indefinite quantity, indefinite-delivery contract)Aerospace: A contract that sets terms and a maximum value but leaves quantities and timing open, with work ordered later through task or delivery orders. Its ceiling is not money the contractor is guaranteed to receive.
IEA (International Energy Agency)Sustainability: The Paris-based intergovernmental energy analysis body.
IEA scenarios (STEPS, Stated Policies Scenario, APS, Announced Pledges Scenario, NZE, Net Zero Emissions by 2050 Scenario)Minerals: Outlook cases the International Energy Agency uses for energy and mineral demand. They include the Stated Policies Scenario, based on policies in place or detailed, the Announced Pledges Scenario and the Net Zero Emissions by 2050 Scenario.
IEC 62443Computing: The international standards series for cybersecurity of industrial automation and control systems.
IEC 62660Batteries: The international standards series for testing the performance and reliability of lithium-ion cells used in electric vehicles.
IEEPA (International Emergency Economic Powers Act)Industry: The International Emergency Economic Powers Act, a 1977 US law that lets the president regulate trade and payments during a declared national emergency, chiefly through sanctions.
ifeu (Institut für Energie- und Umweltforschung Heidelberg)Sustainability: A German environmental research institute.
ILA-USMX master contract (ILA, USMX, International Longshoremen's Association, United States Maritime Alliance)Industry: The labor agreement between US East and Gulf Coast dockworkers and port employers, running to 30 September 2030. It bars fully automated terminals and equipment and requires agreement before semi-automation is introduced.
Ilmenite (FeTiO₃)Minerals: An iron-titanium oxide mineral (FeTiO₃), common in mare basalts and mineral sands. On the Moon it is a leading feed for making oxygen by hydrogen reduction.
In-situ recovery (ISR, in-situ leaching)Minerals: Extracting metal by pumping a leaching solution through an ore body underground and recovering it from wells, without digging the rock. It is the main uranium mining method.
In-situ resource utilization (ISRU)Aerospace: Making useful products, such as oxygen, water or propellant, from materials found on the Moon, Mars or asteroids, to cut what must be launched from Earth.
In-space manufacturing (in-orbit manufacturing, microgravity manufacturing)Aerospace: Making materials or products in orbit to exploit microgravity or vacuum, such as certain drug crystals, optical fibers or tissues. It depends on regular, affordable return flights to bring products back.
Index fund vs. ETFFinance: Both track an index at low cost, but an index mutual fund is bought and sold once a day at its closing net asset value, while an ETF trades on an exchange throughout the day like a stock. In the United States, ETFs are often more tax efficient because of how their shares are created and redeemed.
Indigenization (domestic substitution, import substitution)Industry: Replacing imported technology or inputs with domestically made ones, often under government policy.
Indirect emissionsSustainability: Emissions caused outside the supply chain by the market reaction to extra demand, such as land cleared elsewhere or substitute materials used by displaced buyers.
Indirect land-use change (ILUC)Sustainability: Land clearing that happens elsewhere because fuel demand diverts crops from food and feed markets, raising prices and pulling new land into production. It cannot be observed directly and is estimated with economic models. Published ILUC values for vegetable oils run from about 7 to more than 230 g CO₂e/MJ, wider than the entire direct footprint.
Indium and tellurium (indium, tellurium, indium tin oxide, ITO, cadmium telluride, CdTe)Minerals: By-product metals: indium, recovered from zinc refining, goes into indium tin oxide screen coatings; tellurium, from copper anode slimes, goes into cadmium telluride solar cells.
Induced effects (market-mediated effects)Sustainability: Changes triggered through prices and trade rather than through the supply chain itself. Higher demand for one vegetable oil raises prices, which draws more land into production somewhere else.
Industrial gasesIndustry: Gases such as oxygen, nitrogen, argon, hydrogen, helium and CO₂ produced and delivered at scale for manufacturing, healthcare and energy.
Industrial Internet of Things (IIoT, industrial IoT)Computing: Connected sensors, machines and software used in factories, plants and utilities to monitor and control operations.
Industrial robot (six-axis robot, SCARA, robot arm)Industry: A programmable manipulator arm used in production for welding, painting, handling and assembly. Six-axis arms are the most flexible; SCARA robots are fast four-axis arms for pick-and-place.
Industrial wireless standards (WirelessHART, ISA100.11a)Computing: Wireless protocols designed for plant instrumentation, notably WirelessHART and ISA100.11a, which form reliable mesh networks of sensors.
Inert anode (oxygen-evolving anode, non-consumable anode)Industry: An aluminum smelting anode made of ceramic, metal or cermet that is not consumed and releases oxygen instead of CO₂. It could remove direct smelting emissions but must survive the corrosive bath for years.
Inert gas narcosis (nitrogen narcosis, narcosis)Maritime: An intoxication-like impairment caused by breathing nitrogen or other inert gases at high pressure, which limits air diving depth.
Inertial confinement fusion (ICF, National Ignition Facility, NIF)Industry: Fusion achieved by compressing a tiny fuel pellet with lasers or other drivers so it ignites before it flies apart. The US National Ignition Facility first produced more fusion energy than laser energy delivered in December 2022.
Inertial drift (bias drift, bias stability, scale-factor error, sensor drift)Maritime: The growing position error of an inertial system as small sensor errors, such as bias and scale-factor errors, accumulate over time.
Inertial measurement unit (IMU)Aerospace: A sensor package of accelerometers and gyroscopes that measures a vehicle's acceleration and rotation. It is the core of autopilots and of navigation without satellite positioning.
Inertial navigation system (INS, inertial navigation)Maritime: A system that tracks position, velocity and attitude from accelerometers and gyroscopes alone, without outside signals. Its error grows over time unless corrected.
Inference (AI inference)Computing: Running a trained model to produce outputs, such as answers or predictions. Its share of AI compute grows as models are put to wider use.
Infill drilling (infill drill program)Minerals: Closely spaced drilling within a known deposit to raise confidence in its shape and grade, often to upgrade inferred resources.
Inflation Reduction Act (IRA)Batteries: The 2022 US law that created or expanded clean-energy tax credits, including Sections 45X, 30D and 48E. The 2025 OBBBA law cut back many of them.
Innocent passage (right of innocent passage)Maritime: The right under the Law of the Sea for foreign ships to pass through a country's territorial sea, provided they do not threaten its peace or security.
Insertion lossAerospace: The signal power lost when a component is placed in a transmission path, given in decibels.
Integrated multi-trophic aquaculture (IMTA, polyculture)Maritime: Farming fed species, such as fish, alongside extractive species, such as seaweed and shellfish, that take up their waste nutrients.
Intelligence, surveillance and reconnaissance (ISR)Aerospace: Collecting and processing information about an adversary or area with sensors on aircraft, satellites and other platforms. Many drones and high-altitude platforms are bought mainly for it.
IntercalationBatteries: The reversible insertion of ions into the gaps of a host material's crystal structure without breaking it. Lithium-ion and sodium-ion batteries work by intercalation in both electrodes.
Interconnection queue (grid interconnection, large-load interconnection)Computing: The list of projects waiting for permission and studies to connect to the power grid. Long queues delay new data centers and power plants.
Interest incomeFinance: Income earned on cash, deposits, bonds or loans a company holds. For most non-financial companies it is reported below operating income because it is not part of the core business.
Intermediate oilseed (intermediate crop)Sustainability: An oilseed grown in the gap between main crops in an existing rotation, such as winter canola, carinata (Ethiopian mustard), camelina or pennycress. Because it uses otherwise idle land, it is assumed to cause little or no ILUC.
Internal rate of return (IRR)Finance: The discount rate at which a project's net present value equals zero, used as a measure of its expected annual return. Higher is better, but it can mislead when comparing projects of very different size or duration.
Internal resistanceBatteries: The opposition to current flow inside a cell, which turns some energy into heat. It rises as a cell ages or gets cold, which limits power and fast charging.
Internal short circuit (internal short)Batteries: A direct electrical connection between a cell's electrodes inside the cell, from separator failure, dendrites, damage or manufacturing defects. It is a leading trigger of thermal runaway.
International Cable Protection Committee (ICPC)Maritime: An industry body of cable owners, operators and governments that sets recommendations for protecting and repairing submarine cables.
International Financial Reporting Standards (IFRS)Finance: Accounting standards issued by the International Accounting Standards Board and required or permitted in most countries outside the United States. They cover the same ground as US GAAP but differ in areas such as inventory and development costs.
International Lunar Research Station (ILRS)Aerospace: A China-led program, with Russia and other partners, to build a research base near the Moon's south pole in the 2030s.
International Maritime Organization (IMO)Maritime: The UN agency in London that sets global rules for shipping safety, security and pollution, such as SOLAS and MARPOL.
International Seabed Authority (ISA, Seabed Authority, ISA Council, Legal and Technical Commission)Minerals: The body set up under UNCLOS, based in Kingston, Jamaica, that grants exploration contracts and is drafting rules for mining in the Area.
Internet of Things (IoT, AIoT)Computing: Everyday and industrial objects fitted with sensors and network connections so they can report data and be controlled remotely.
Interposer (silicon interposer, photonic interposer, optical interposer)Computing: A thin layer, often silicon, on which several chips are mounted side by side and wired together with very fine connections. It links GPUs to high-bandwidth memory.
InterstageAerospace: The structure that joins two rocket stages and houses the upper-stage engine until separation. It carries loads between the stages and usually stays with the lower stage.
InverterBatteries: A power electronic device that converts direct current (DC) from batteries or solar panels into alternating current (AC). Inverter losses and size are part of every storage system's cost.
Ion exchange (ion-exchange resin)Minerals: Separating or purifying dissolved metals by passing a solution through resin beads that swap one ion for another.
Ion-adsorption clay (ionic clay, ionic adsorption clay, ion-adsorption deposit, IAC)Minerals: Weathered clay in which rare earths are loosely held on clay surfaces and can be leached cheaply. Deposits in southern China and Myanmar supply most heavy rare earths.
Ionic conductivity (mS/cm)Batteries: How easily ions move through an electrolyte, in millisiemens per centimetre (mS/cm). Liquid electrolytes reach ≈10 mS/cm; solid electrolytes must approach that to allow fast charging.
IoT gateway (edge gateway, network gateway)Computing: A device that links local sensors or networks to a wider network or the cloud, often filtering and converting the data.
IPCC (Intergovernmental Panel on Climate Change)Sustainability: The UN body that assesses climate science and publishes the default emission factors and warming potentials that carbon accounting relies on.
IPCEI (Important Project of Common European Interest)Batteries: Important Project of Common European Interest, an EU state-aid route that lets member states fund large cross-border industrial projects, such as battery value chains, beyond normal aid limits.
Iron-air battery (iron air)Batteries: A battery that stores energy by reversibly rusting iron with oxygen from the air. It is very cheap per kilowatt-hour but heavy and inefficient, which suits multi-day grid storage.
IRS Notice 2026-53Sustainability: U.S. Treasury guidance on the amended Section 45Z credit, under which used cooking oil imported from outside the United States, Mexico and Canada is ineligible after 2025.
ISCC (International Sustainability and Carbon Certification)Sustainability: The largest voluntary certification scheme recognized under the EU RED. It attests waste status and sustainability along biofuel supply chains. It has faced criticism over audit weaknesses at the point where waste status is attested.
Ising modelComputing: A physics model of interacting spins that point up or down. Finding its lowest-energy state is equivalent to many optimization problems, which is why annealers use it.
ISO 14040 and ISO 14044Sustainability: The International Organization for Standardization's core standards for life cycle assessment. ISO 14040 sets principles and framework; ISO 14044 sets requirements, including the allocation hierarchy. They are method standards, not compliance schemes, and they allow either attributional or consequential framing.
ISO 14067Sustainability: The ISO standard for calculating the carbon footprint of a product. It requires transparent, separate reporting of biogenic carbon and direct land-use change.
ISO/ASTM 52900Industry: The international standard that sets the terms and the seven process categories of additive manufacturing.
Isomerization (isomerized)Sustainability: Rearranging straight-chain paraffins into branched ones with the same formula, usually over a noble-metal catalyst such as platinum. Branched molecules stay liquid at lower temperatures, improving cold-flow properties.
Isostatic pressing (warm isostatic press)Batteries: Compressing a part evenly from all sides with pressurized fluid or gas. Solid-state cell makers use warm isostatic presses to bond electrolyte and electrode layers without voids.
ITAR (International Traffic in Arms Regulations)Aerospace: The US State Department rules that control exports of defense articles, services and technical data on the US Munitions List. Sharing controlled data with a foreign person, even inside the US, can count as an export.
ITSCI (International Tin Supply Chain Initiative)Minerals: The International Tin Supply Chain Initiative, a traceability and due diligence program that tags tin, tantalum and tungsten minerals from mine sites in central Africa.
ITU (International Telecommunication Union, ITU-R)Aerospace: The UN agency that coordinates use of radio spectrum and satellite orbits worldwide. Satellite operators file with it to secure frequencies and orbital positions.

J

Jamming and spoofing (jamming, spoofing, anti-jam, anti-spoofing)Aerospace: Jamming drowns out a signal with noise; spoofing feeds a receiver false signals, such as fake satellite navigation data, so it computes the wrong position. Both are routine against drones.
JANUS (STANAG 4748, JANUS protocol)Maritime: The NATO standard (STANAG 4748), promulgated in 2017, for digital underwater acoustic messaging, giving equipment from different makers a common first contact signal.
JARUS (Joint Authorities for Rulemaking on Unmanned Systems)Aerospace: A group of national aviation authorities that drafts shared rules and guidance for drones and other uncrewed systems, which members may adopt.
JORC Code (JORC, JORC 2012, Australasian Joint Ore Reserves Committee)Minerals: The Australasian code for public reporting of exploration results, mineral resources and ore reserves, used by companies listed in Australia and New Zealand. The current edition dates from 2012.
Josephson junctionComputing: Two superconductors separated by a very thin barrier through which current tunnels. It is the nonlinear element in superconducting qubits and superconducting logic.
Joule heating (resistive heating, resistance heating)Batteries: Heating by passing an electric current through a resistive material. Electric thermal stores use it to charge, converting electricity to heat at nearly 100% efficiency.
JP-7Aerospace: A low-volatility, heat-stable jet fuel developed for the SR-71 reconnaissance aircraft. It resists boiling and coking at high temperatures but is expensive and hard to ignite.
JRC (Joint Research Centre)Sustainability: The European Commission's in-house science service. It builds the typical and default values in the RED from modeled supply chains rather than plant data.

K

Kerolox (RP-1, LOX/kerosene)Aerospace: Rocket propellant made of refined kerosene, called RP-1, and liquid oxygen. It is dense and easy to store but leaves carbon deposits in engines, known as coking.
kg CO₂e/kg H₂Sustainability: Kilograms of CO₂-equivalent emitted per kilogram of hydrogen produced, the standard measure of hydrogen's carbon intensity.
Kick stage (kick-stage)Aerospace: A small extra stage that gives a payload a final push after the main rocket has done its work. It is used to circularize an orbit, change orbits, or deorbit a spacecraft that has no engine of its own.
KnotAerospace: A speed of one nautical mile per hour, ≈1.852 km/h. Aviation and shipping use it worldwide.
Knowledge graph (knowledge graphs)Computing: A database of entities and the relationships between them, such as companies, people and contracts. Graph-based retrieval uses it to answer questions that span many documents.
KREEP (KREEP basalt)Minerals: Lunar material enriched in potassium (K), rare earth elements (REE) and phosphorus (P), concentrated around the Procellarum region.
Küchemann limit (Küchemann barrier)Aerospace: An empirical ceiling on the best lift-to-drag ratio achievable at a given Mach number M, often written as (L/D)max ≈ 4(M + 3)/M. At Mach 6 it gives ≈6, which caps the range of hypersonic aircraft.

L

Land-use change (LUC)Sustainability: Any shift in how land is used or covered, such as forest to cropland, and the carbon it releases or stores. It includes both direct and indirect effects.
Landauer limit (Landauer's principle)Computing: The minimum energy needed to erase one bit of information, about kT ln 2, ≈3 × 10⁻²¹ J at room temperature. Today's chips use vastly more than this per operation.
Large language model (LLM, LLMs)Computing: A neural network trained on very large amounts of text to predict the next token, which lets it answer questions, write and reason in language. Chat assistants are built on them.
Laser powder bed fusion (LPBF, L-PBF, selective laser melting, SLM, powder-bed fusion)Industry: An additive process that melts thin layers of metal powder with a laser, one layer at a time. It gives fine detail and is the most common metal printing method.
Laser source (VCSEL, vertical-cavity surface-emitting laser, DFB laser, distributed feedback laser)Computing: The light source for optical links. VCSELs emit from the chip surface and suit short links; distributed feedback lasers give a single clean wavelength for longer links.
Latent heat storage (latent heat, phase-change material, PCM)Batteries: Storing heat in a material as it melts or changes phase, at a nearly constant temperature. It packs more energy into less space than sensible storage.
Laterite (nickel laterite, lateritic ore)Minerals: Iron-rich soil and rock formed by deep tropical weathering. Nickel laterites supply much of the world's nickel and some cobalt.
Launch cadence (cadence, flight rate)Aerospace: How often a launch vehicle or launch site flies, usually counted in launches per year. Cadence depends on production rate, refurbishment time, pad turnaround and licensing limits.
Launch complex (Space Launch Complex, launch pad)Aerospace: A site with one or more launch pads plus the propellant storage, integration buildings and support equipment needed to prepare and fly rockets. US sites are numbered, as in Launch Complex 39A or Space Launch Complex 40. A vehicle with only one pad stops flying if that pad is damaged.
Launch vehicle (launcher)Aerospace: A rocket that carries payloads such as satellites, cargo or crew from Earth's surface to space. Most are built in two or more stages that drop away as their propellant runs out. Launch vehicles are compared by the mass they can lift to a given orbit.
Layered mafic intrusion (layered intrusion, reef)Minerals: A large body of iron- and magnesium-rich magma that cooled in layers, concentrating chromium, platinum group metals and nickel into thin, continuous ore layers called reefs.
Layered oxide cathode (layered transition-metal oxide, NaxTMO₂)Batteries: A cathode built of stacked sheets of transition-metal oxide, such as copper, iron or manganese oxides for sodium-ion. It gives the highest sodium-ion energy density but is sensitive to moisture.
LBMA (London Bullion Market Association, London OTC market)Minerals: The London Bullion Market Association, which sets trading and refining standards for the London over-the-counter market in gold, silver, platinum and palladium.
LCFS (Low Carbon Fuel Standard)Sustainability: California's program, adopted in 2009, that requires fuel suppliers to cut the average carbon intensity of their fuels each year, with tradeable credits for fuels below the benchmark. Amendments effective 1 July 2025 cap crop-oil credits at 20 percent of each company's volume and bar palm-derived fuels.
Leaching (acid leaching, bioleaching)Batteries: Dissolving metals out of a solid, such as black mass or ore, with acid or another solution. It is the first chemical step in hydrometallurgy.
Lead-acid battery (lead acid, AGM, absorbent glass mat)Batteries: The oldest rechargeable battery, using lead electrodes in sulfuric acid. It is cheap and almost fully recycled but heavy and short-lived; it still starts most combustion vehicles.
Leading edgeAerospace: The front edge of a wing, fin or inlet. On hypersonic vehicles leading edges take the most heat, so their sharpness trades aerodynamic efficiency against temperature.
Lethal autonomous weapon system (LAWS)Aerospace: A weapon that can select and engage targets without further human input once activated. Its regulation is debated internationally, including under the Convention on Certain Conventional Weapons.
Levelized cost of electricity (LCOE)Industry: The lifetime cost of building and running a power plant divided by the electricity it produces, in $/MWh, used to compare technologies.
Levelized cost of storage (LCOS)Batteries: The lifetime cost of a storage system divided by the energy it delivers, in $/MWh. It folds in capital cost, efficiency, cycle life and operating costs for comparing technologies.
LeverageFinance: The use of borrowed money to increase exposure or fund operations, which magnifies both gains and losses. It is commonly measured with ratios such as debt to equity or debt to EBITDA.
Leveraged buyout (LBO)Finance: The acquisition of a company funded mostly with borrowed money, secured by the target's own assets and cash flows. The buyer, often a private equity firm, aims to reduce the debt and later sell the company at a gain.
LFP (lithium iron phosphate, LiFePO₄)Batteries: Lithium iron phosphate, a lithium-ion cathode chemistry. It uses no nickel or cobalt, is cheap, long-lived and thermally stable, but stores less energy per kilogram than nickel-based cathodes.
Liberation (mineral liberation)Minerals: The degree to which grinding frees valuable mineral grains from gangue so they can be separated.
LiDAR (lidar, Lidar)Industry: Light detection and ranging, a sensor that measures distance by timing reflected laser pulses to build a 3D map. Autonomous vehicles and robots use it to see their surroundings.
Life cycle (lifecycle)Sustainability: All the stages of a product's existence, from raw materials to end of life. A lifecycle emission figure adds up every stage inside the chosen boundary.
Life cycle assessment (LCA)Sustainability: The standardized method, set out in ISO 14040 and 14044, for totaling the environmental impacts of a product across its life cycle. It can be run on an attributional or consequential basis.
Life of mine (LOM, mine life)Minerals: The planned operating span of a mine, from first production until reserves are exhausted under the mine plan.
Lift-plus-cruise (lift-and-cruise, lift+cruise)Aerospace: An eVTOL layout with one set of rotors for vertical lift and a separate propeller for forward flight on a wing. The lift rotors are dead weight in cruise, but the design avoids tilting mechanisms.
Lift-to-drag ratio (L/D, glide ratio)Aerospace: The ratio of the lift a vehicle produces to its drag, a key measure of aerodynamic efficiency. It sets glide distance and, with engine efficiency, cruise range. It falls sharply at hypersonic speeds.
Light and heavy rare earths (light rare earths, heavy rare earths, LREE, LREEs, HREE, HREEs, medium rare earths)Minerals: Rare earths are grouped by atomic weight. Light ones, such as lanthanum, cerium, neodymium and praseodymium, are more abundant; heavy ones, such as dysprosium, terbium and yttrium, are scarcer and costlier.
Light ends, renewable naphtha and propaneSustainability: The lighter co-products of HVO production. Light ends are gases and volatile liquids; renewable naphtha is a gasoline-range liquid used in petrochemicals or blending; propane comes from the glycerol backbone and can displace fossil LPG.
Light sweet crude (sweet crude, sour crude)Industry: Crude oil that is low in density and sulfur, which yields more high-value fuels with less processing. Heavy sour crude is the opposite.
Light-water reactor (LWR, pressurized-water reactor, PWR, boiling-water reactor, BWR)Industry: A reactor cooled and moderated by ordinary water, the type used in most of the world's nuclear plants. Pressurized-water reactors keep the water liquid under pressure; boiling-water reactors let it boil.
Limit orderFinance: An instruction to buy at or below, or sell at or above, a stated price. Execution is not guaranteed.
Line-edge roughness (LER, line-width roughness, LWR)Computing: Random variation along the edges of printed lines. At small sizes it can cause shorts or open circuits and limits resist performance.
Link budgetAerospace: An accounting of every gain and loss along a radio link, from transmitter power and antenna gain to path loss and noise. It shows whether the link works with enough margin.
Liquefied petroleum gas (LPG)Industry: Propane and butane, gases at normal conditions that are stored as liquids under modest pressure. It is used for cooking, heating and as a petrochemical feedstock.
Liquid breathing (liquid ventilation, perflubron, partial liquid ventilation, total liquid ventilation, perfluorocarbon liquid ventilation)Maritime: Breathing an oxygen-rich perfluorocarbon liquid instead of gas. Partial liquid ventilation adds liquid to the lungs alongside gas; total liquid ventilation replaces gas entirely.
Liquid cooling (direct-to-chip cooling, immersion cooling)Computing: Cooling servers by circulating liquid to cold plates on the chips, or by immersing servers in a non-conductive fluid. It handles far higher heat loads than air.
Liquid oxygen (LOX)Aerospace: Oxygen cooled to a liquid at ≈90 K (≈−183 °C). It is the oxidizer in most liquid-fueled rockets.
Lithium carbonate (Li₂CO₃)Batteries: A lithium compound that is the main traded form of lithium and the usual feed for LFP cathodes. Lithium prices are often quoted per tonne of battery-grade lithium carbonate.
Lithium carbonate equivalent (LCE)Batteries: A common unit for comparing lithium content across compounds, expressed as the mass of lithium carbonate that would contain the same lithium. One tonne of lithium metal equals ≈5.3 tonnes LCE.
Lithium hydroxide (LiOH, lithium hydroxide monohydrate)Batteries: A lithium compound preferred for high-nickel cathodes because it reacts at lower temperatures. It is usually made from spodumene or converted from lithium carbonate.
Lithium platingBatteries: Deposition of metallic lithium on the anode surface instead of inside it, typically when charging fast or in the cold. It reduces capacity and can lead to dendrites.
Lithium-ion battery (Li-ion, LIB, lithium-ion, lithium-ion cell)Batteries: A rechargeable battery in which lithium ions move between a graphite or silicon anode and a metal-oxide or phosphate cathode. It dominates electric vehicles, electronics and grid storage.
Lithium-manganese-rich cathode (LMR, LMR-NMC, lithium-rich manganese)Batteries: A cathode family with extra lithium and manganese that can store more charge than standard NMC while using less nickel and cobalt. Voltage fade over cycling has slowed its adoption.
Lithium-metal anode (lithium metal, Li-metal)Batteries: An anode made of pure lithium foil, giving the highest possible energy density. Dendrites and short cycle life have kept it mostly out of liquid-electrolyte cells; solid-state designs aim to make it practical.
Lithium-polymer battery (LiPo, Li-Po, lithium polymer)Batteries: A lithium-ion battery using a gel or polymer electrolyte, usually in a soft pouch. Common in drones and phones, it allows thin, light, flexible shapes.
Lithium-sulfur battery (Li-S, lithium sulfur)Batteries: A battery pairing a lithium-metal anode with a sulfur cathode. It promises very high specific energy at low cost, but the cathode dissolves over cycling, which limits life.
LLZO (garnet electrolyte, Li₇La₃Zr₂O₁₂)Batteries: Lithium lanthanum zirconium oxide, a garnet-structured ceramic solid electrolyte. It is stable against lithium metal but is brittle and needs sintering at ≈1,000 °C or more.
LMFP (lithium manganese iron phosphate)Batteries: Lithium manganese iron phosphate, a variant of LFP with manganese added to raise cell voltage. It gains ≈15–20% energy density over LFP while keeping most of its cost and safety advantages.
Load following (load-following)Industry: Changing a power plant's output to match changing demand through the day. Nuclear and large thermal plants traditionally run flat but newer designs aim to follow load.
Locked-cycle test (locked cycle test)Minerals: A laboratory flotation test that recycles middle streams over several runs to predict steady-state plant recovery and grade.
LOFAR analysis (LOFAR, LOFARgram)Maritime: Low-frequency analysis and recording, a spectral display that reveals the steady tonal lines from a vessel's machinery, used to classify it.
Logical qubit (logical qubits, logical error rate)Computing: An error-corrected qubit built from many physical qubits. Its logical error rate must fall as more physical qubits are added for error correction to work.
Loitering munition (one-way attack drone, kamikaze drone)Aerospace: A weapon that flies to an area, circles while searching for a target, then dives into it. It blends a drone with a missile and is usually expendable.
London Metal Exchange (LME)Minerals: The main exchange for industrial metal futures and warehouse delivery, setting benchmark prices for copper, aluminum, nickel and zinc.
Long Duration Storage ShotBatteries: A US Department of Energy goal, set in 2021, to cut the cost of grid storage lasting more than 10 hours by 90% within the decade.
Long-duration energy storage (LDES, long-duration storage, multi-day storage, seasonal storage)Batteries: Storage that can deliver power for many hours to days, to cover gaps that daily batteries cannot. Definitions vary: the US Department of Energy uses more than 10 hours. Flow, iron-air, thermal and pumped hydro compete here.
Long-tail riskFinance: The risk of rare events with outsized consequences, the outcomes that sit at the far ends of a return distribution. They are easy to underestimate because they appear infrequently in historical data.
Long-term debtFinance: Borrowings due more than twelve months after the balance sheet date. The part due within the next year is shown separately as the current portion of long-term debt.
Look-ahead biasFinance: Using information in a backtest before it would have been available in practice, such as applying quarterly earnings on the last day of the quarter rather than the reporting date.
LoRa and LoRaWAN (LoRa, LoRaWAN)Computing: LoRa is a long-range, low-power radio technique; LoRaWAN is the network protocol built on it. They suit battery sensors and off-grid mesh networks.
Loss leaderFinance: A product sold at or below cost to attract customers who are expected to buy other, profitable products. Retailers and razor-and-blade business models are the classic examples.
Low Earth orbit (LEO)Aerospace: Orbits from ≈160 km up to 2,000 km altitude, where satellites circle Earth in ≈90–130 minutes. The short distance means little signal delay, but each satellite sees a small area, so coverage needs many.
Low observability (low observable, stealth)Aerospace: Design features that make a vehicle hard to detect by radar, infrared, acoustic or visual sensors, such as shaping, absorbent materials and controlled emissions.
Low-altitude economyAerospace: A Chinese policy term for commercial activity in low airspace, generally below 1,000 m, including drone delivery, eVTOL passenger flights and aerial services. Beijing treats it as a strategic emerging industry.
Low-carbon aluminum (green aluminum, low-carbon aluminium)Industry: Aluminum made with low emissions per tonne, usually from hydropower-fed smelters or recycled metal. It can sell at a premium over standard metal.
Low-rate initial production (LRIP, low-rate production)Aerospace: The first, limited production run of a defense system, used to prove the production line and supply test articles before full-rate production is approved.
Lower heating value (LHV)Sustainability: The energy released when a fuel burns, excluding the heat recoverable by condensing the water vapor produced. Fuel lifecycle figures are normally quoted on an LHV basis.
Loyal wingmanAerospace: An uncrewed combat aircraft that flies alongside a crewed fighter and takes direction from its pilot, extending sensors and weapons and taking on the riskiest tasks.
LPWAN (low-power wide-area network, NB-IoT)Computing: Low-power wide-area network, a class of wireless networks that send small amounts of data over kilometres on very little power, such as LoRaWAN and NB-IoT.
Lunar Gateway (Gateway)Aerospace: A small space station planned for lunar orbit as a staging point for Artemis missions, built with international partners. Its funding has been contested in US budget debates.
Lunar regolith (regolith, lunar soil, lunar dust)Minerals: The layer of loose dust and broken rock covering the Moon, the main feedstock for making oxygen, metals and building material in place.

M

Mach number (Mach)Aerospace: Speed expressed as a multiple of the local speed of sound. Sound travels slower in cold air, so the same Mach number means a lower true speed at high altitude.
MACH-TB (Multi-Service Advanced Capability Hypersonics Test Bed)Aerospace: A US Defense Department program, run by its Test Resource Management Center, that raises the number and pace of affordable hypersonic flight tests using commercial vehicles and test services.
Machine learning (ML)Computing: Software that learns patterns from data instead of following hand-written rules. Most modern AI, from image recognition to language models, is built this way.
Machine tendingIndustry: Loading and unloading parts into machines such as CNC mills, a common first job for robots and cobots.
Machine tool (machine tools)Industry: A powered machine that shapes metal or other rigid material by cutting, grinding or forming, such as a lathe, mill or press. Supply is concentrated in a few countries.
Made in China 2025Industry: China's 2015 industrial plan to become a leader in advanced manufacturing sectors such as chips, robotics, aerospace and electric vehicles, with high domestic content targets.
Magnet grade (magnet grades, N52, N42)Minerals: A code for a magnet's strength and heat rating. In NdFeB grades such as N52 or 38EH, the number gives energy product and the suffix the temperature class.
Magnet powder processing (strip casting, hydrogen decrepitation, jet milling, aligned pressing, vacuum sintering)Minerals: The main steps in making sintered magnets. The alloy is strip cast into flakes, cracked by hydrogen decrepitation and jet milled to a few microns, then pressed in a magnetic field and vacuum sintered.
Magnet recycling (magnet-to-magnet recycling, HPMS, hydrogen processing of magnet scrap, HDDR)Minerals: Recovering rare earths from scrap magnets, either by dissolving them chemically or by hydrogen processing that turns old magnets directly into powder for new ones.
Magnetic bearing (active magnetic bearing, AMB, superconducting magnetic bearing, passive magnetic bearing)Batteries: A bearing that supports a rotor with magnetic fields instead of contact, reducing friction to nearly zero. Active types use controlled electromagnets; passive and superconducting types need less power.
Magnetic permeability (permeability, relative permeability)Industry: How easily a material carries magnetic flux, relative to empty space. High permeability is the main goal for core materials.
Magnetic separation (magnetic separator)Minerals: Separating minerals by how strongly they respond to a magnet, used to upgrade iron ores, mineral sands and rare earth ores.
Magnetic windowAerospace: A blackout-mitigation concept that applies a strong magnetic field near an antenna to change how the surrounding plasma behaves, so radio signals can get through.
Main-season cropSustainability: A crop that occupies a field for its full growing season, displacing whatever else could have been grown there.
Make-up hydrogenSustainability: The fresh hydrogen fed to a hydroprocessing unit to replace what the reactions consume and what is lost in purge and dissolved gases. It is higher than the chemical minimum.
ManifestAerospace: A launch provider's list of contracted missions and their planned order. A full manifest signals demand; a slipping one signals delays.
Mannheim processIndustry: A process that makes sulfate of potash by reacting potassium chloride with sulfuric acid at high temperature.
Manufacturing execution system (MES)Industry: Software that tracks and directs production on the factory floor in real time, linking orders, machines, materials and quality records.
Manufacturing scrap (production scrap)Batteries: Electrodes and cells rejected during battery production. It has been the largest source of recycling feed so far, because few electric-vehicle batteries have yet reached end of life.
Manufacturing USA (manufacturing innovation institutes)Industry: A US network of public-private institutes, each focused on one advanced manufacturing technology, such as additive manufacturing or photonics.
Manufacturing yield (yield, first-pass yield)Batteries: The share of cells or electrodes made that pass quality tests. New lines often start with low yields; reaching ≈90% or more is a key test of a factory ramp.
Mare and highland regolith (mare, maria, lunar highlands, mare basalt)Minerals: Mare regolith covers the dark basalt plains and is rich in iron and titanium; highland regolith covers the pale uplands and is rich in aluminum and calcium.
Marginal cost pricingFinance: Setting a price equal to the cost of producing one more unit. In commodity markets the price tends toward the cost of the highest-cost producer still needed to meet demand, which is why that producer is called the marginal producer.
Marginal landSustainability: Land of low agricultural value, often degraded or unproductive, that is not needed for food. Fuel crops grown there are promoted as avoiding competition with food, though yields are usually lower.
Marine energy (ocean energy, marine renewable energy)Maritime: Power from waves, tides, currents and ocean temperature or salinity differences.
Marine spatial planning (MSP, ocean zoning, ecosystem-based management)Maritime: A public process for deciding which human activities take place where at sea, balancing uses such as shipping, energy, fishing and conservation.
Market orderFinance: An instruction to buy or sell immediately at the best available price. Execution is near certain; price is not.
MARSEC levels (MARSEC, MARSEC directive)Industry: The three US maritime security threat levels set by the Coast Guard for ports and ships; Coast Guard MARSEC directives impose security measures, including on cyber risk.
Mask blank (EUV mask blank, Mo/Si multilayer)Computing: The unpatterned substrate from which a photomask is made. EUV blanks carry dozens of alternating molybdenum and silicon layers that reflect EUV light.
Mass allocationSustainability: Splitting shared emissions in proportion to the weight of each co-product. It is GREET's default for soybean, and it favors the oil, which is light relative to the meal.
Mass balanceSustainability: A chain-of-custody method that allows certified and uncertified material to be physically mixed, provided the quantity sold as certified never exceeds the certified quantity bought. It tracks volumes on paper, which makes it hard to prove what is physically in a tank.
Master alloy (master alloys)Minerals: A concentrated alloy of a key element, such as dysprosium-iron, added to a melt to control its composition.
Material assistance (material assistance cost ratio, MACR)Batteries: Under US tax law since 2025, the share of a facility's or component's direct costs that comes from prohibited foreign entities. Projects exceeding set thresholds, which tighten each year, lose clean-energy credits.
Matrix multiplication (GEMM, general matrix multiplication)Computing: Multiplying grids of numbers, the operation that dominates neural network training and inference. Accelerators are designed to do it as fast and efficiently as possible.
Matte (PGM-rich matte, nickel matte)Industry: A molten mix of metal sulfides produced in smelting, from which copper, nickel or platinum-group metals are later refined.
Maximum energy product (BHmax, (BH)max, energy product, MGOe)Minerals: The headline measure of a magnet's strength, the peak product of flux density and field, in MGOe or kJ/m³. Top NdFeB grades exceed 50 MGOe.
Maximum takeoff weight (MTOW, gross takeoff weight, maximum takeoff mass)Aerospace: The heaviest weight at which an aircraft is certified to take off, including fuel, payload and crew. It is the main size measure in aviation rules and fees.
Meal and cakeSustainability: The protein-rich solids left after oil is extracted from oilseeds. They are sold as animal feed and take a share of upstream emissions as co-products.
Means of compliance (MoC)Aerospace: The accepted methods an applicant uses to show that a design meets a regulation, such as specific tests, analyses or industry standards.
Mechanical pre-processing (pre-processing, shredding)Batteries: The first recycling steps: discharging, dismantling, shredding and separating batteries into black mass, metals and plastics.
Medium Earth orbit (MEO)Aerospace: Orbits between low Earth orbit and geostationary altitude, roughly 2,000–35,786 km. Navigation constellations such as GPS and Galileo fly here, at ≈20,000–23,000 km.
Medium-lift, heavy-lift and super heavy-lift (small-lift, medium-lift, heavy-lift, super heavy-lift, super heavy lift launch vehicle, SHLLV)Aerospace: Size classes for launch vehicles, based on the mass they can place in low Earth orbit (LEO). The commonly cited NASA thresholds are below. See the table
Megaconstellation (satellite constellation, constellation)Aerospace: A network of hundreds to thousands of satellites, usually in low Earth orbit, working together to give continuous coverage. Such fleets need frequent launches both to deploy and to replace satellites as they wear out.
Megajoule (MJ)Sustainability: A unit of energy equal to one million joules. A litre of diesel holds about 36 MJ; a kilowatt-hour equals 3.6 MJ.
Melt poolIndustry: The small pool of molten metal created where the energy beam hits the powder or wire. Its size and stability control part density and defects.
Memory wallComputing: The growing gap between how fast processors can compute and how fast memory can supply them with data. It often limits AI performance more than raw compute does.
MemristorComputing: A circuit element whose resistance depends on the current that has flowed through it and is retained without power. Arrays of memristors can store weights and compute in place.
Mesh network (mesh networking)Computing: A network in which devices relay data for each other, so messages can hop around failures without a central tower or router.
Metaheuristic (metaheuristics, genetic algorithm, evolutionary algorithm, simulated annealing)Computing: A general strategy for finding good, though not guaranteed best, answers to hard optimization problems, such as genetic algorithms or simulated annealing.
Metal-oxide resist (MOR, dry resist)Computing: An EUV photoresist built from metal-oxide clusters, often tin-based, which absorbs EUV light more strongly and resists etching better than organic resists. Some versions are deposited dry from vapor.
Metallization (metallisation, oxide-to-metal conversion)Minerals: Converting purified rare earth oxides into metal or alloy, by molten salt electrolysis or metallothermic reduction. It is a narrow bottleneck outside China.
Metallothermic reduction (calciothermic reduction, magnesiothermic reduction)Minerals: Producing a metal by reacting its oxide or halide with a more reactive metal such as calcium or magnesium. It is used for samarium, dysprosium, terbium and titanium.
Metallurgical recovery (recovery, plant recovery, metal recovery)Minerals: The share of metal in the feed that ends up in saleable product. Recovery and grade together set how much metal a plant produces.
MetasurfaceAerospace: A thin layer of engineered, repeating structures smaller than the wavelength, which shapes radio waves or light in ways ordinary materials cannot.
Methalox (LOX/methane)Aerospace: Rocket propellant made of liquid methane and liquid oxygen. Methane burns cleaner than kerosene, leaving less soot in engines, which suits reuse, and in principle it can be made on Mars.
Methane (CH₄)Sustainability: A greenhouse gas about 27 times as potent as CO₂ over 100 years and over 80 times over 20 years. In this sector it comes chiefly from decaying palm mill effluent and from leaks in natural-gas supply chains.
Methane capture (biogas capture)Sustainability: Covering palm oil mill effluent ponds or treating the effluent in digesters so that methane is collected and burned or used rather than vented.
Methane leakage (upstream methane)Sustainability: Natural gas that escapes during extraction, processing and transport before it reaches the plant. Because methane is a potent greenhouse gas, even a few percent of leakage can erase much of blue hydrogen's benefit. At 8 percent leakage blue hydrogen's reduction versus grey falls from about 75 to about 45 percent.
Metres of seawater (msw, feet of seawater, fsw)Maritime: A unit of pressure expressed as depth in seawater; every ≈10 msw adds about one atmosphere of pressure.
Metric tonne unit (mtu, MTU, metric ton unit)Minerals: The price unit for tungsten concentrate and APT: 10 kg of WO₃, containing ≈7.93 kg of tungsten.
Metrology (CD-SEM, scatterometry, wafer inspection)Computing: Measuring features and layers on wafers to control the process, with tools such as CD-SEMs, which use electron microscopes, and optical scatterometry.
Micro-CT (microtomography, X-ray microtomography, phase-contrast microtomography)Computing: X-ray computed tomography at micrometre resolution, which builds a 3D image of an object's interior from many X-ray views. Phase-contrast micro-CT can reveal materials with almost no density difference.
Microcontroller (MCU, microcontrollers)Computing: A small, low-power computer on a single chip with its own memory and input-output pins, used to control devices such as sensors and appliances.
Microfactory (micro-factory, distributed manufacturing)Industry: A small, highly automated production site that makes goods close to customers in short runs, instead of in one large central plant.
MicrogravityAerospace: The near-weightless condition inside an orbiting spacecraft, which is in continuous free fall. It changes how fluids, crystals and cells behave, which is the basis for research and manufacturing in orbit.
MicrogridBatteries: A local grid with its own generation and storage that can run connected to the main grid or alone, in island mode. Ports, campuses and remote sites use microgrids for resilience.
Microreactor (micro-reactor, nuclear microreactor)Industry: A very small nuclear reactor, typically up to ≈20 MWe, that can be transported by truck or ship to power remote sites or military bases for years without refueling.
Microring resonator (microring, micro-ring resonator, MRR)Computing: A tiny ring-shaped waveguide that strongly affects light only at certain wavelengths. It is compact and wavelength-selective but sensitive to temperature.
Middle tier of acquisition (middle-tier acquisition)Aerospace: A US defense acquisition path for rapid prototyping or rapid fielding, meant to deliver capability to users within five years without the full traditional process.
Military specification (MIL-SPEC, mil-spec, MIL-STD)Industry: A US defense standard defining the properties, testing and packaging a material or product must meet for military purchase.
Mine permitting (plan of operations, notice-level activity)Minerals: Approvals needed to explore, build and operate a mine, such as environmental reviews, water and air permits and operating plans. On US federal land, larger disturbance needs an approved plan of operations.
Mine-to-magnet (mine to magnet)Minerals: A supply chain that covers every step from mining and separation through metal, alloy and finished magnets, often within one country or group.
Mineral reserves vs. resourcesFinance: A mineral resource is a concentration with reasonable prospects of eventual economic extraction, classed as inferred, indicated or measured. A mineral reserve is the part of indicated and measured resources shown to be economically mineable by at least a pre-feasibility study, classed as probable or proven.
Mineral soilSustainability: Ordinary soil made mostly of weathered rock particles, as opposed to organic peat soil. Palm grown on mineral soil has a far smaller footprint than palm on drained peat.
Minerals Security Partnership (MSP)Minerals: A US-led group of governments, launched in 2022, that coordinates investment in critical mineral projects outside China.
Mining Code (exploitation regulations, ISA Mining Code, draft exploitation regulations)Minerals: The International Seabed Authority's set of rules for seabed exploration and exploitation. Exploration rules exist, but exploitation regulations were still unadopted after the July 2026 session.
Mining dilution (dilution, ore dilution)Minerals: Waste rock that ends up mixed with ore during mining, lowering the grade sent to the mill.
Mining royalty (royalty, royalties, sliding-scale royalty, net smelter return royalty, NSR royalty)Minerals: A payment to a government or landowner based on the value or volume of minerals produced. Sliding-scale royalties rise with the metal price.
Minor metals (minor metal, technology metals)Minerals: Metals produced in small volumes, often as by-products and without exchange-traded futures, such as gallium, germanium, indium, tellurium, rhenium and hafnium.
MIRAGESustainability: A global economic model from the International Food Policy Research Institute, used in the EU's 2011 ILUC study. It is an earlier counterpart to GLOBIOM in the European debate.
Mishap investigationAerospace: A formal inquiry into a launch or flight failure, led by the operator and overseen in the US by the FAA. Flights usually resume only after the regulator accepts the findings and corrective actions.
Mission assuranceAerospace: The engineering, testing and independent review that raise confidence a mission will succeed. Government customers demand more of it for their most valuable payloads, which adds cost and time.
Mississippi Valley-type deposit (MVT, MVT deposit)Minerals: A lead-zinc deposit formed by warm basin brines in carbonate rock, named after the US region where it was first described.
Mixer-settler (mixer-settlers, countercurrent cascade)Minerals: A tank pair in solvent extraction where two liquids are mixed and then allowed to separate. Rare earth plants link hundreds in countercurrent cascades.
Mode transitionAerospace: The handoff in a combined-cycle engine from turbine power to ramjet or scramjet power, usually between ≈Mach 2 and Mach 4. Thrust tends to dip during it, so the vehicle needs margin to keep accelerating.
Model drift (data drift)Computing: The gradual loss of a model's accuracy as real-world data shifts away from the data it was trained on. It is managed by monitoring and retraining.
Model outputSustainability: A number produced by simulation rather than measured. All ILUC values are model outputs. That an effect is unobservable is not evidence that it is zero.
Model portfolioFinance: A hypothetical portfolio run according to published rules. No client capital is traded.
Model-based definition (MBD, model-based enterprise)Industry: Putting dimensions, tolerances and other product data directly in the 3D model instead of on separate drawings, so machines and inspectors can read it automatically.
Model-based systems engineering (MBSE)Aerospace: Designing and managing a complex system with linked digital models instead of separate documents, so requirements, design and tests stay consistent.
Modifying factorsMinerals: The mining, processing, economic, legal, environmental and social factors applied to convert a mineral resource into a reserve.
MOFCOM (Ministry of Commerce of China, China Ministry of Commerce)Minerals: China's Ministry of Commerce, which issues export-control announcements and licenses exports of controlled minerals, materials and technologies.
Molten regolith electrolysis (MRE, molten oxide electrolysis, MOE)Minerals: Melting regolith at ≈1,600 °C and passing current through it to release oxygen at the anode and metals such as iron and silicon at the cathode, with no added salts.
Molten salt electrolysis (fused salt electrolysis, molten-salt electrolysis)Minerals: Producing a reactive metal by passing current through its compound dissolved in molten salt. Neodymium and didymium metal are made this way.
Molten salt reactor (MSR)Industry: A reactor in which fuel is dissolved in molten salt or salt serves as coolant, running at low pressure and high temperature.
Molten salt storage (molten salt, solar salt)Batteries: Thermal storage using a mixture of nitrate salts, kept liquid at ≈290–565 °C. Concentrated solar power plants use it to keep generating after sunset.
MomentumFinance: The tendency of securities that have performed well over the past six to twelve months to continue to do so over the next one to twelve months. Commonly measured as 12-month return skipping the most recent month.
Monte Carlo analysisSustainability: A technique that runs a model thousands of times with randomly varied inputs to map the range of possible results.
Moon Agreement (Moon Treaty, Agreement Governing the Activities of States on the Moon and Other Celestial Bodies)Minerals: A 1979 UN treaty declaring lunar resources the common heritage of mankind. Few states have joined, and none of the major spacefaring powers.
More-electric aircraft (MEA)Aerospace: A design approach that replaces hydraulic, pneumatic and mechanical aircraft systems with electrical ones. It raises demand for compact generators, motors and power electronics on board.
MTConnectIndustry: An open standard, first released in 2008, that lets machine tools report their status and data in a common format for monitoring and analytics.
MTEB (Massive Text Embedding Benchmark)Computing: The Massive Text Embedding Benchmark, a public leaderboard comparing embedding models across retrieval, clustering and classification tasks.
Multi-beam mask writer (MBMW, multibeam mask writer)Computing: An electron-beam tool that writes a photomask with hundreds of thousands of beams at once, making complex curved mask shapes practical.
Multi-column electron-beam lithography (MEBL, multi-column e-beam)Computing: E-beam lithography using many independent electron columns in parallel to raise throughput enough for some direct writing on wafers.
Multibeam echo sounder (MBES, multibeam sonar)Maritime: A sonar that sends a fan of beams to map a wide swath of seafloor depth in one pass.
Multipath (multipath propagation)Maritime: A signal arriving at a receiver by several paths, such as direct and reflected, at slightly different times. It distorts underwater acoustic links and degrades radio positioning.
Multipatterning (multi-patterning, double patterning, SADP, SAQP, LELE, self-aligned double patterning, self-aligned quadruple patterning)Computing: Printing a dense layer in two or more exposure and etch steps so each step prints sparser features. It extends older lithography to finer pitches at the cost of more steps, time and overlay risk.
Multiply-accumulate (MAC, MACs, multiply-accumulate operation)Computing: The basic operation of neural network computing: multiply two numbers and add the result to a running total. Hardware efficiency is often quoted as energy per MAC.
Multirotor (multicopter)Aerospace: An aircraft lifted and controlled by several fixed-pitch rotors whose speeds are varied independently. It is mechanically simple and hovers well but is inefficient in forward flight.

N

Nameplate capacityBatteries: A factory's rated maximum annual output, in GWh for battery plants. Actual output is usually lower because of ramp-up time, yield and demand.
NAND flash (NAND, flash memory)Computing: Non-volatile memory that keeps data without power, used in SSDs, phones and memory cards. It is cheaper per bit than DRAM but slower and wears out with writes.
Nanoimprint lithography (NIL, nanoimprint, J-FIL)Computing: Pressing a patterned template into liquid resist on a wafer and curing it, like stamping, instead of projecting light. It is cheap and fine-grained but struggles with defects and overlay.
NASICON (NASICON-type)Batteries: A family of phosphate ceramic ion conductors whose name comes from sodium superionic conductor. Variants serve as solid electrolytes for lithium and as cathode frameworks for sodium batteries.
National Defense Stockpile (NDS, strategic stockpile)Industry: The US government's reserve of strategic and critical materials, held for national defense emergencies and bought and sold by the Defense Logistics Agency.
National Quantum Initiative ActComputing: The 2018 US law that set up a coordinated federal program for quantum research across NIST, the National Science Foundation and the Department of Energy.
National Security Space Launch (NSSL)Aerospace: The US Space Force program that buys launches for the most important military and intelligence satellites. Rockets must be certified, and the program keeps more than one provider to assure access to space.
National space resources laws (Luxembourg space resources law, space resources law)Minerals: Laws that let companies own resources they extract in space, adopted by Luxembourg in 2017, the UAE in 2019 and Japan in 2021, alongside the 2015 US law.
Natural gas benchmarks (Henry Hub, TTF, Title Transfer Facility, MMBtu, million British thermal units)Industry: Reference prices for natural gas, the main feedstock and cost for ammonia. Henry Hub is the US benchmark; the Dutch TTF is Europe's. Prices are quoted per million British thermal units.
Nautical mile (nmi)Aerospace: A distance of 1,852 m by international definition, used in aviation and shipping because it relates to minutes of latitude.
Naval blockade (blockade)Maritime: Using naval force to stop ships from entering or leaving an enemy's ports or coast. Island and import-dependent states are most exposed.
Naval mine warfare (mine warfare, mine countermeasures, MCM, naval mines, covert mining)Maritime: Laying sea mines to deny waters to an enemy, and countering them by hunting, sweeping or avoiding them. Uncrewed vehicles increasingly do both.
Navigation integrity (integrity monitoring, navigation system integrity)Maritime: Confidence that a navigation system's output is correct, including timely warnings when it should not be used.
Navy Experimental Diving Unit (NEDU)Maritime: The US Navy's diving and hyperbaric research and testing command in Panama City, Florida, which sets Navy diving procedures.
NCA (nickel cobalt aluminum, NMCA)Batteries: Nickel cobalt aluminum oxide, a high-nickel lithium-ion cathode. It gives high energy density and is used mainly in some electric vehicle cylindrical cells.
NDAA (National Defense Authorization Act)Aerospace: The National Defense Authorization Act, the annual US law that sets defense policy and authorizes spending levels. It often carries sourcing bans, such as limits on Chinese-made drones, magnets and electronics.
NDAA-compliant (NDAA compliant)Aerospace: Describes drones and components free of parts from manufacturers or countries barred by US defense authorization laws, chiefly Chinese suppliers. Compliance is a precondition for many government purchases.
NdFeB magnet (NdFeB, neodymium magnet, neodymium-iron-boron, Nd₂Fe₁₄B, neo magnet)Minerals: A neodymium-iron-boron permanent magnet, the strongest commercial type. It powers most electric vehicle motors, wind generators and robots but weakens at high temperature without dysprosium or terbium.
NdPr (NdPr oxide, neodymium-praseodymium, didymium, PrNd)Minerals: A mixed neodymium-praseodymium oxide or metal, the main rare earth input to NdFeB magnets and the industry's price benchmark. Didymium is the metal form.
Near-Earth asteroid (NEA, NEAs, near-Earth object)Minerals: An asteroid whose orbit brings it close to Earth's. Some can be reached with less energy than the Moon's surface.
Near-net shape (net shape)Industry: Making a part close to its final form at the start, by casting, forging or printing, so little material must be machined away.
NEC Article 706 (National Electrical Code Article 706)Batteries: The part of the US National Electrical Code that covers wiring and installation of energy storage systems, including home batteries.
NEPA (National Environmental Policy Act)Aerospace: The US National Environmental Policy Act, which requires federal agencies to assess environmental effects before major actions, such as licensing a launch site or a higher flight rate.
Net change in cashFinance: The combined result of operating, investing and financing cash flows for a period, plus any currency effect. It equals the ending cash balance minus the beginning cash balance.
Net import reliance (import reliance, net import dependence)Minerals: The share of a country's apparent consumption of a material met by net imports. The USGS reports it each year for every major mineral.
Net pen (open-net pen, sea cage, net cage)Maritime: A floating cage in a lake or sea where fish are raised, with waste and escapes flowing into surrounding waters.
Net present value (NPV) in miningFinance: The sum of a project's future cash flows discounted to today, minus its upfront cost. In mining studies it is the headline figure, usually after tax at a stated discount rate such as 8%, and it moves sharply with commodity price assumptions.
Net-negativeSustainability: A product or activity that removes more greenhouse gas than it emits over its life cycle.
Net-zeroSustainability: A state in which remaining emissions are exactly balanced by durable removals. It differs from "low-carbon", which only means fewer emissions than an alternative.
Network difficulty (mining difficulty, bitcoin difficulty)Computing: A bitcoin setting that adjusts about every two weeks so blocks keep arriving every ≈10 minutes. Rising difficulty means each machine earns less.
Network segmentationComputing: Dividing a network into separate zones so an intrusion in one cannot easily spread to others, such as keeping plant control systems apart from office IT.
Neural network (artificial neural network, CNN, convolutional neural network, recurrent neural network)Computing: A model made of layers of simple connected units whose weights are adjusted during training. Variants include convolutional networks for images and recurrent networks for sequences.
Neuromorphic computing (neuromorphic chip)Computing: Hardware designed to mimic the brain's structure, often with spiking neurons and memory placed next to processing, to cut the energy cost of AI.
NFPA 13Industry: The US National Fire Protection Association standard for installing automatic fire sprinkler systems. Its occupancy and storage rules shape factory and warehouse design.
NFPA 855Batteries: The US National Fire Protection Association standard for installing stationary energy storage systems. It sets size limits, spacing, ventilation and fire protection, and is widely adopted into local codes.
NI 43-101 (National Instrument 43-101, 43-101 technical report, CIM Definition Standards, CIM)Minerals: Canada's rule for disclosing scientific and technical information about mineral projects. Reports must be prepared by a qualified person and follow CIM definitions.
Nickel sulfate and cobalt sulfate (nickel sulfate, cobalt sulfate, manganese sulfate)Batteries: The dissolved-metal chemicals from which NMC and NCA cathode precursors are made. Manganese sulfate plays the same role for manganese.
NISQ (noisy intermediate-scale quantum)Computing: Noisy intermediate-scale quantum: the current era of quantum computers with tens to hundreds of qubits but no full error correction, which limits how long a computation can run.
NIST PQC standards (FIPS 203, FIPS 204, FIPS 205, ML-KEM, ML-DSA, SLH-DSA, HQC)Computing: The US post-quantum cryptography standards: FIPS 203 (ML-KEM) for key exchange, FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA) for digital signatures, all published in August 2024. NIST chose HQC as a backup key-exchange method in March 2025.
Nitrates Directive (Directive 91/676/EEC)Industry: Council Directive 91/676/EEC, the EU law that limits nitrogen use from manure and fertilizers to protect water from nitrate pollution.
Nitrogen fixationSustainability: The process by which legumes such as soybean, with help from root bacteria, convert atmospheric nitrogen into plant nutrients, reducing the need for synthetic fertilizer.
Nitrous oxide (N₂O)Sustainability: A greenhouse gas about 273 times as potent as CO₂ over 100 years, released mainly when soil microbes process nitrogen fertilizer. It is the largest and least certain emission term in crop-based fuels.
Nm³ (normal cubic metre)Sustainability: A volume of gas measured at standard conditions of 0 °C and one atmosphere, used to state hydrogen consumption.
NMC (nickel manganese cobalt, NCM, NMC811, NMC622, NMC532, NMC111)Batteries: Nickel manganese cobalt oxide, the main high-energy lithium-ion cathode family. Grades are named by metal ratio: NMC811 is 8 parts nickel to 1 manganese to 1 cobalt. Higher nickel raises energy density but reduces stability.
Nodule collector (collector vehicle, collector, riser, riser system, lift system)Minerals: A seabed vehicle that picks up nodules and pumps them through a riser pipe to a surface ship. The riser and flexible hoses link the two.
Noise temperatureAerospace: A measure of the electrical noise a receiver or antenna adds, given as an equivalent temperature in kelvin. Lower is better; hot, lossy elements such as plasma raise it.
Non-recurring engineering (NRE)Aerospace: The one-time cost of designing, developing and tooling a product before production. It is spread over the units built, so low volumes mean high unit costs.
Non-terrestrial network (NTN)Aerospace: The 3GPP term for parts of a mobile network carried by satellites or high-altitude platforms instead of ground towers. Standards from Release 17 onward let phones and base stations work through them.
Non-volatile memory (NVM, MRAM, ReRAM, resistive RAM, magnetoresistive RAM)Computing: Memory that keeps data when power is off, such as flash, MRAM, ReRAM and phase-change memory.
NP-hardComputing: A class of problems for which no known method finds the exact best answer quickly as the problem grows. Routing and scheduling problems are typical examples.
NPK fertilizer (complex fertilizer, compound fertilizer, NPK)Industry: A blended or compound fertilizer containing nitrogen, phosphorus and potassium in stated ratios.
NPU (neural processing unit)Computing: Neural processing unit, a processor block designed for AI tasks, often built into phones, laptops and other devices.
NRC (Nuclear Regulatory Commission, US Nuclear Regulatory Commission)Industry: The US Nuclear Regulatory Commission, which licenses and oversees civilian nuclear reactors and materials.
NSSL Phase 3 Lane 1 and Lane 2 (NSSL Phase 3, Lane 1, Lane 2)Aerospace: The two tracks of the current NSSL procurement. Lane 1 buys launches for less demanding missions and is open to newer providers. Lane 2 covers the most demanding missions, requires full certification, and spans orders placed in fiscal years 2025–2029.
Nuclear thermal propulsion (NTP)Aerospace: A rocket engine that heats hydrogen in a nuclear reactor and expels it through a nozzle. It offers about twice the specific impulse of the best chemical engines, which could shorten trips to Mars.
Nuclear-powered submarines (SSN, SSBN, attack submarine, ballistic missile submarine)Maritime: Submarines driven by onboard reactors that can stay submerged for months. Attack submarines (SSN) hunt ships and submarines; ballistic missile submarines (SSBN) carry nuclear deterrent missiles.
Numerical aperture (NA)Computing: A measure of the range of angles a lens or mirror system collects light from. Higher numerical aperture gives finer resolution but less depth of focus.
Nutrient Based Subsidy (NBS)Industry: India's scheme that pays fertilizer companies a fixed subsidy per kilogram of nitrogen, phosphorus, potassium and sulfur in phosphate and potash fertilizers, keeping farm prices low.
Nutrient basis (P₂O₅, K₂O, K₂O equivalent, N-P-K)Industry: Fertilizer quantities are often stated as nutrient content: N for nitrogen, P₂O₅ for phosphate and K₂O for potash, regardless of the product form.
NVMe (Non-Volatile Memory Express)Computing: Non-Volatile Memory Express, the standard protocol for connecting SSDs over the PCIe bus, giving far lower delay than older SATA connections.

O

OBBBA (One Big Beautiful Bill Act)Sustainability: The 2025 U.S. budget law that amended Section 45Z, excluding ILUC for fuel produced after 2025 and restricting feedstocks to North America.
Obligated fundingAerospace: Money the government has legally committed to a contract, as opposed to its ceiling or announced value. It is the firmest measure of contract revenue to come.
Ocean acidificationMaritime: The fall in seawater pH as the ocean absorbs carbon dioxide from the air, which makes it harder for shellfish and corals to build shells and skeletons.
Ocean data center (underwater data center, subsea data center, floating data center)Maritime: A data center sited at sea or on the seabed, using seawater for cooling and sometimes ocean energy for power.
Ocean thermal energy conversion (OTEC)Maritime: Generating power, and often fresh water, from the temperature difference between warm tropical surface water and cold deep water.
OECD Due Diligence Guidance (OECD Due Diligence Guidance for Responsible Supply Chains of Minerals, OECD guidance, OECD 3TG supplement)Minerals: The OECD's framework for responsible mineral supply chains from conflict-affected and high-risk areas, the reference standard behind US and EU conflict minerals rules.
Office of Naval Research (ONR)Maritime: The US Navy and Marine Corps science and technology organization that funds naval research and early development.
Office of Strategic Capital (OSC)Aerospace: A US Defense Department office, created in 2022, that makes loans and loan guarantees to companies producing critical technologies.
Offset (external offset)Sustainability: A credit bought from a project outside the supply chain, such as forest protection, to cancel emissions on paper. Offsets do not change the product's physical footprint.
Offtake (offtake agreement)Sustainability: A contract in which a buyer commits in advance to purchase a share of a producer's future output, often for several years. Offtakes give lenders confidence to finance a plant.
Oil refinery (refinery, petroleum refinery)Industry: A plant that separates crude oil into fuels and feedstocks by distillation and then converts heavier fractions into lighter, more valuable products.
Old and new scrap (old scrap, new scrap, home scrap, post-consumer scrap)Minerals: Old scrap comes from products at the end of their life; new scrap is offcuts and rejects from manufacturing, which are easier to recycle.
OleochemicalsSustainability: Chemicals made from fats and oils, such as soaps, detergents, lubricants and cosmetics ingredients. The industry is a long-standing buyer of tallow and other lipid residues.
One engine inoperative (OEI)Aerospace: The condition of a multi-engine aircraft flying with one engine failed. Certification requires defined performance in this state, such as continuing to climb or landing safely.
OPC UA (OPC Unified Architecture, umati)Industry: OPC Unified Architecture, an open standard for secure, structured data exchange between industrial machines and software. Companion specifications define common models for specific machine types.
Open Compute Project (OCP)Computing: An industry group that publishes open hardware designs for data center servers, storage, racks and power.
Open effluent pondSustainability: An uncovered lagoon where palm mill wastewater decays without oxygen, releasing large amounts of methane. It is the default practice at many mills.
Open-pit mining (open pit, open-cut mining, surface mining, strip mining)Minerals: Surface mining from a large excavation dug in benches. It suits large, near-surface deposits and moves more waste than ore.
Operating expenses vs. total expensesFinance: Operating expenses are the costs of running the core business, such as selling, general and administrative costs and research and development. Total expenses add the cost of goods sold, interest, taxes and other non-operating costs.
Operating incomeFinance: Gross profit minus operating expenses: the profit from a company's core business before interest and taxes. It is often used interchangeably with operating profit or EBIT.
Operational technology (OT)Computing: The hardware and software that monitor and control physical equipment, such as pumps, valves and production lines, as distinct from office IT.
Operations researchComputing: The use of mathematical models and optimization to make better decisions in logistics, scheduling, networks and resource allocation.
Optical circuit switch (OCS)Computing: A switch that redirects light beams between fibers without converting them to electrical signals, saving power in large AI clusters.
Optical I/O (optical I/O chiplet, optical interconnect)Computing: Optical input-output connections built close to or onto a chip, carrying data off-chip as light instead of electrical signals.
Optical intersatellite link (laser crosslink, optical crosslink, laser communications terminal)Aerospace: A laser link that carries data directly between satellites, avoiding ground relays. It offers high data rates and is hard to intercept, but needs very precise pointing.
Optical modulator (modulator, Mach-Zehnder modulator, MZM, MZI, Mach-Zehnder interferometer, microring modulator, MRM, electro-absorption modulator, EAM)Computing: A device that encodes data onto light by changing its intensity or phase. Common types are Mach-Zehnder interferometers, microring modulators and electro-absorption modulators.
Orbital data center (orbital compute, space-based data center)Aerospace: A proposed computing facility in orbit, powered by solar arrays and cooled by radiating heat into space. Backers cite abundant solar power; launch cost, heat rejection and maintenance are the main obstacles.
Orbital debris (space debris, space junk)Aerospace: Defunct satellites, spent stages and fragments left in orbit. At orbital speeds even small pieces can damage spacecraft, so operators track debris and maneuver to avoid it.
Orbital inclination (inclination)Aerospace: The angle between an orbit's plane and Earth's equator. Changing it in space costs a lot of propellant, so launch-site latitude and rocket performance limit which inclinations are reachable.
Orbital propellant transfer (in-orbit refueling, on-orbit refueling, cryogenic propellant transfer, ship-to-ship transfer)Aerospace: Moving rocket propellant from one spacecraft to another in orbit, so a vehicle can refill after launch and continue to the Moon or beyond. Doing it with cryogenic propellants, which slowly boil off, is far harder than with storable ones.
Orbital transfer vehicle (OTV, space tug)Aerospace: A spacecraft that moves payloads from the orbit a rocket drops them in to the orbit they actually need. It lets satellites on one rideshare reach different final orbits.
Ore (ore body, orebody)Minerals: Rock containing enough of a valuable mineral to be mined and processed at a profit. Whether rock counts as ore depends on prices and costs, not geology alone.
Ore grade (grade, head grade, feed grade)Minerals: The concentration of a valuable metal or mineral in ore, given as a percentage, in grams per tonne or in parts per million. Higher grade means more metal per tonne mined.
Ore sorting (sensor-based ore sorting)Minerals: Using sensors such as X-ray or optical scanners to reject waste rock from ore before grinding, cutting processing cost.
Organic Rankine cycle (ORC)Industry: A Rankine cycle that uses an organic fluid with a low boiling point instead of water, to make power from low-temperature heat such as waste heat or geothermal sources.
OrionAerospace: NASA's crew capsule for deep-space missions, launched on the Space Launch System. A European-built service module supplies its power and propulsion.
OSAT (outsourced semiconductor assembly and test)Computing: Outsourced semiconductor assembly and test: companies that package and test chips for chipmakers.
Other transaction authority (OTA, other transaction agreement)Aerospace: Legal authority for US defense agencies to sign agreements outside standard procurement rules, mainly for prototypes and research. It is faster and suits commercial firms, and a successful prototype can move to follow-on production without a new competition.
Outer Space TreatyAerospace: The 1967 UN treaty that underpins space law. It bars national claims of sovereignty over celestial bodies and weapons of mass destruction in orbit, and makes states responsible for their companies' space activities.
Overburden (prestrip, pre-stripping)Minerals: Soil and rock lying above an ore body that must be removed before surface mining.
OverlayComputing: How accurately each new layer lines up with the layers already on the wafer, measured in nanometres. Overlay errors break connections between layers.
OWASP Top 10 for LLM applications (OWASP, Open Worldwide Application Security Project)Computing: A list of the most serious security risks for applications built on large language models, published by the Open Worldwide Application Security Project. Prompt injection ranks first.
Oxide electrolyte (oxide solid electrolyte, ceramic electrolyte)Batteries: A solid electrolyte made of ceramic oxides, such as garnet LLZO or NASICON-type phosphates. Oxides are stable in air but brittle and need high temperatures to process.

P

Pack price (battery pack price, volume-weighted average pack price)Batteries: The average price of a complete battery pack per kilowatt-hour, the standard benchmark of battery costs. BloombergNEF's annual survey is the most cited series.
Palm fatty acid distillate (PFAD)Sustainability: A by-product of refining crude palm oil, rich in free fatty acids. It is often treated as a residue, but it has established markets in feed, soap and oleochemicals and is tied to palm's land use.
Palm oil mill effluent (POME)Sustainability: The wastewater from palm oil mills. Its decay produces methane, and oil skimmed from it is traded as a low-value residue feedstock.
PAM4 (PAM-4, pulse amplitude modulation)Computing: Four-level pulse amplitude modulation, which sends two bits per symbol by using four signal levels. It doubles data rate over simple on-off signalling.
Paraffinic dieselSustainability: Diesel made of paraffins (alkanes) rather than a crude-oil mixture, meeting the European standard EN 15940. HVO and gas-to-liquids diesel are both paraffinic.
Part 36Aerospace: The FAA rules setting the noise limits and test procedures aircraft must meet for type certification.
Part 103 (ultralight)Aerospace: The FAA rule for ultralight vehicles: single-seat recreational aircraft that need no pilot certificate or registration. A powered ultralight must weigh under 254 lb empty, carry at most 5 US gal of fuel and fly no faster than 55 knots.
Part 107Aerospace: The FAA rule for routine commercial flights of small drones under 55 lb, flown within the operator's line of sight. Flights outside its limits need a waiver.
Part 108Aerospace: The FAA's proposed rule for routine beyond-visual-line-of-sight drone operations, replacing case-by-case waivers with permits and certificates. It was proposed in August 2025; as of October 2026 the final rule had not been published.
Part 450Aerospace: The FAA's consolidated rule for licensing commercial launch and reentry, in effect since March 2021. It sets performance-based requirements and lets one license cover many missions and sites; older licenses had to move to it by March 2026.
Part consolidationIndustry: Redesigning an assembly of many pieces as one printed part, cutting fasteners, assembly steps and failure points.
Parts 23, 25, 27 and 29 (Part 23, Part 25, Part 27, Part 29)Aerospace: The FAA airworthiness standards for the main aircraft types, with matching EASA specifications. New aircraft such as powered-lift often draw on several of them under special-class rules. See the table
Passive safety (passive cooling, natural circulation)Industry: Reactor safety features that work without power, pumps or operator action, using gravity, natural circulation or heat conduction to shut down and cool the core.
PayloadAerospace: What a launch vehicle or aircraft carries to perform its mission, such as satellites, cargo, crew, sensors or weapons. Rocket payload capacity is quoted as mass to a named orbit, for example kilograms to low Earth orbit.
Payload fairing (fairing)Aerospace: The protective shell at the top of a rocket that shields the payload from air pressure and heating during the climb through the atmosphere. It is jettisoned once the rocket is high enough. Its inner diameter limits how large a payload can fly.
Payload user guide (payload user's guide)Aerospace: A launch provider's public technical document listing payload mass to each orbit, fairing dimensions, and the loads, vibration and environment a payload must survive.
PCIe (PCI Express)Computing: PCI Express, the standard high-speed connection between a processor and devices such as GPUs, SSDs and network cards. Each generation roughly doubles bandwidth per lane.
Peak shaving (peak-shaving, demand charge management)Batteries: Using stored energy to cut the highest points of a site's or grid's demand, which lowers demand charges and delays grid upgrades.
Peak watt (Wp, kWp, MWp, watt-peak)Batteries: The rated output of a solar panel under standard test conditions. A 3 MWp solar array produces 3 MW only in ideal sunlight.
Peat (peatland)Sustainability: Waterlogged soil made of partly decayed plant matter, built up over thousands of years and holding very large carbon stocks. Southeast Asian tropical peat swamps are a major frontier of palm expansion.
Peat oxidationSustainability: The continuous release of CO₂ when drained peat is exposed to air and decomposes. It recurs every year for as long as the land stays drained. Estimates for drained tropical peat run from about 38 to 95 t CO₂ per hectare per year.
Pegmatite (pegmatites)Minerals: A very coarse-grained igneous rock formed from the last, element-rich melt of a magma. Pegmatites host many lithium, tantalum and niobium deposits.
Pellicle (EUV pellicle, carbon nanotube pellicle)Computing: A thin transparent membrane stretched over a photomask to keep particles out of focus. EUV pellicles must survive intense heat while letting most light through.
PEM electrolyzer (PEM electrolyser, proton exchange membrane electrolyzer)Industry: An electrolyzer that splits water into hydrogen and oxygen across a proton exchange membrane. It responds quickly to variable power but needs platinum and iridium catalysts.
Penny stocks vs. small-cap stocksFinance: A penny stock is defined by its low share price, usually under $5, and often trades over the counter with thin liquidity. A small-cap stock is defined by company size, typically a market capitalisation of about $250 million to $2 billion, and frequently trades on a major exchange.
Perfluorocarbons (PFCs, PFC, CF₄, C₂F₆)Industry: Very long-lived, potent greenhouse gases, mainly CF₄ and C₂F₆, released by aluminum smelters during anode effects. Each tonne warms thousands of times more than a tonne of CO₂.
Performance metrics for compute (FLOPS, PFLOP/s, TOPS, TOPS/W, exaflop, exascale)Computing: Common measures of processor capability. FLOPS count floating-point operations per second; TOPS count trillion operations per second, often low precision; TOPS/W measures energy efficiency.
Periscope depthMaritime: The shallow depth at which a submarine can raise its periscope or masts to communicate or take a satellite fix, at higher risk of detection.
Permanence and reversalSustainability: Permanence is how long stored carbon stays out of the atmosphere. A reversal is its return, for example when tilled soil releases carbon or a forest burns.
Permanent magnet (permanent magnets, rare earth magnet, rare earth magnets, REPM)Minerals: A material that stays magnetized without power, used in motors, generators, speakers and sensors. Rare earth magnets are the strongest.
Permanent magnet synchronous motor (PMSM, PMSG, permanent magnet motor, externally excited synchronous motor, EESM, wound-rotor motor)Minerals: An electric motor with permanent magnets in its rotor, the most efficient and common type for electric vehicles. Wound-rotor and induction motors avoid rare earths.
Permanently shadowed regions (PSR, PSRs, cold traps, permanently shadowed craters)Minerals: Polar craters on the Moon that never receive sunlight and stay below ≈110 K, cold enough to trap water ice and other volatiles.
Personally identifiable information (PII)Computing: Data that can identify a person, such as a name, ID number or location. Privacy laws restrict how it is stored and shared.
Phase-change memory (PCM memory, phase-change chalcogenide, GST, Ge-Sb-Te)Computing: Memory that stores bits by switching a chalcogenide glass between crystalline and amorphous states, which differ in resistance and optical properties. It is used in electronic memory and photonic computing research.
Phased array (phased-array antenna, electronically scanned array, AESA)Aerospace: An antenna made of many small elements whose signal timing is adjusted electronically to steer the beam without moving parts. Radars, satellite terminals and satellites use it.
Phosphate fertilizers (DAP, MAP, diammonium phosphate, monoammonium phosphate)Industry: Fertilizers that supply phosphorus, mostly diammonium phosphate (18-46-0) and monoammonium phosphate (11-52-0), made by reacting phosphoric acid with ammonia.
Phosphate rock (phosphorite)Industry: Sedimentary rock rich in phosphate minerals, mined chiefly in Morocco and Western Sahara, China and the US. It is the raw material for phosphate fertilizer.
PhosphogypsumIndustry: A slightly radioactive gypsum byproduct of phosphoric acid production, ≈5 t per tonne of P₂O₅, usually stored in large stacks.
Photodetector (photodiode, APD, avalanche photodiode)Computing: A device that converts light into an electrical signal. Avalanche photodiodes add internal gain for weak signals.
Photolithography (lithography, optical lithography)Computing: Printing chip patterns by shining light through a patterned mask onto light-sensitive resist on a wafer. It is the step that sets the smallest features a fab can make.
Photomask (mask, reticle)Computing: A plate carrying a chip layer's pattern that is projected onto the wafer during lithography. A full chip needs dozens of masks, each costing a great deal at advanced nodes.
Photonic computing (optical computing, photonic neural network, PNN, photonic tensor core)Computing: Doing computation, usually matrix multiplication for AI, with light instead of electrons. It promises speed and efficiency but converting data between light and electronics eats much of the gain.
Photonic integrated circuit (PIC, PICs, photonic chip)Computing: A chip that routes and processes light, combining many optical components on one die.
Photonic materials (indium phosphide, InP, silicon nitride, SiN, III-V)Computing: The main material platforms for photonic chips. Silicon is cheap and CMOS-compatible but cannot emit light; indium phosphide makes lasers; silicon nitride gives low-loss waveguides.
Photoresist (EUV resist)Computing: A light-sensitive coating on the wafer that changes chemically where exposed, so the pattern can be developed and etched. Resist chemistry limits resolution and dose.
Physical verificationSustainability: Checking the material itself, through sampling, lab testing or site inspection, rather than only the paperwork.
Pidgeon processIndustry: A method of making magnesium by heating calcined dolomite with ferrosilicon in a vacuum. It is energy-intensive and dominates Chinese production.
Piezoelectric transducer (PZT, acoustic transducer)Maritime: A ceramic element that turns electrical signals into sound and sound into electrical signals, the core of most sonar and acoustic modems.
Pilot line (pilot plant, demonstration line)Batteries: A small production line used to prove a cell design and process before full-scale manufacturing. Pilot output is far too small to show whether costs will fall at scale.
Placer deposit (placer, alluvial deposit, placers)Minerals: Heavy minerals such as gold, tin or zircon concentrated by rivers, waves or wind in sand and gravel.
Planetary protectionAerospace: Practices that keep spacecraft from contaminating other worlds with Earth life, and Earth with material returned from space.
Plasma antennaAerospace: An antenna that uses a column of ionized gas instead of metal as its conductor. It can be switched off to become nearly invisible to radio waves and retuned electronically, but it is less efficient than metal.
Plasma frequencyAerospace: The natural oscillation frequency of electrons in a plasma, set by electron density. Radio waves below it are reflected or absorbed; waves above it pass through.
Plasma sheathAerospace: The layer of ionized gas that surrounds a vehicle at hypersonic or reentry speeds. It reflects and absorbs radio waves, causing communications blackout.
Platinum group metals (PGM, PGMs, platinum-group metals)Industry: Six rare metals found together in ore: platinum, palladium, rhodium, ruthenium, iridium and osmium. They are prized as catalysts and are mined mainly in South Africa and Russia.
Plot-level geolocationSustainability: Recording the exact coordinates of the farm or plantation plot where a feedstock was grown, so that buyers can check it against deforestation and peat maps.
Pluggable transceiver (pluggable optics, optical transceiver, 800G, 1.6T, linear-drive pluggable optics, LPO)Computing: A removable module that converts electrical signals to optical and back, plugged into the front of a switch or server. Speeds such as 800G and 1.6T refer to its data rate.
PNT (positioning, navigation and timing, positioning, navigation, and timing, resilient PNT, complementary PNT)Maritime: Positioning, navigation and timing, the services that tell users where they are and what time it is. Most depend on satellite signals, so backups are a security priority.
Polyanionic cathode (polyanion cathode, NVPF, NFPP)Batteries: A cathode built around phosphate or similar groups, such as NVPF or NFPP for sodium-ion, or LFP for lithium-ion. Strong chemical bonds give long life and stability at some cost in energy density.
Polymer electrolyte (PEO, polyethylene oxide electrolyte, solid polymer electrolyte)Batteries: A solid electrolyte made of a polymer, typically polyethylene oxide, with a dissolved lithium salt. It is easy to process but conducts ions well only when warm, ≈60–80 °C.
Polymetallic nodules (manganese nodules, nodules, polymetallic nodule)Minerals: Potato-sized lumps on the abyssal seafloor rich in manganese, nickel, copper and cobalt, formed over millions of years. The Clarion-Clipperton Zone holds the largest fields.
Polypropylene (PP)Industry: A widely used plastic made by polymerizing propylene, which refineries with petrochemical units produce from cracker off-gases.
Polysulfide shuttle (shuttle effect)Batteries: The main failure mode of lithium-sulfur cells: sulfur compounds dissolve into the electrolyte, drift to the anode and react there, wasting capacity on every cycle.
Porphyry copper deposit (porphyry, porphyry deposit)Minerals: A very large, low-grade copper deposit formed around a cooling igneous intrusion. Porphyries supply most of the world's copper and much of its molybdenum and rhenium.
Port automation (automated terminal, semi-automated terminal)Industry: Running terminal equipment such as stacking cranes, vehicles and gates with software and remote or autonomous control. It raises consistency and safety but faces labor agreements and high upfront costs.
Position sizingFinance: The rule that determines how much capital is allocated to a single idea.
Post-quantum cryptography (PQC, quantum-safe cryptography)Computing: Encryption and signature methods designed to resist attack by quantum computers. NIST published its first standards, FIPS 203, 204 and 205, in August 2024.
Potash (MOP, muriate of potash, KCl, SOP, sulfate of potash)Industry: Potassium-bearing salts used as fertilizer. Muriate of potash (potassium chloride) dominates; sulfate of potash suits chloride-sensitive crops. It is mined chiefly in Canada, Russia and Belarus.
Potline (potroom)Industry: A long series of electrolytic cells, called pots, connected electrically in an aluminum smelter. It runs continuously at hundreds of kiloamperes and cannot be stopped without major cost.
Power conversion system (PCS, bidirectional inverter)Batteries: The inverters and related equipment that convert a battery's direct current to grid alternating current and back.
Power rating and energy rating (MW/MWh, power capacity, energy rating)Batteries: A storage system's power rating, in MW, is how fast it can deliver energy; its energy rating, in MWh, is how much it holds. A 100 MW / 400 MWh system can run at full power for 4 hours.
Power take-off (PTO)Maritime: The mechanism in a wave or tidal device, such as a hydraulic system, linear generator or turbine, that converts motion into electricity.
Power usage effectiveness (PUE)Computing: Total data center power divided by the power used by the computing equipment. A value of 1.0 would be perfect; efficient modern sites reach ≈1.1–1.2.
Powered-lift (powered lift)Aerospace: A category of aircraft that takes off and lands vertically using engine-driven lift but relies on a wing in cruise, such as tiltrotors and many eVTOLs. US regulators set out pilot and operating rules for it in a 2024 final rule.
Pre-feasibility study (PFS)Finance: An intermediate engineering and economic study that tests whether a mineral project is viable and selects the preferred way to develop it. Its cost estimates are typically accurate to about 25%, and it is the minimum study needed to declare mineral reserves.
Precursor (pCAM, cathode precursor)Batteries: An intermediate compound from which cathode active material is made, such as mixed nickel-manganese-cobalt hydroxide. It is mixed with a lithium compound and fired to form the finished cathode.
Predictive maintenanceComputing: Using sensor data and analytics to predict when equipment will fail so it can be fixed just before, reducing downtime.
Preliminary economic assessment (PEA, scoping study)Minerals: An early study of a mineral project's potential economics, which may use inferred resources. It cannot support a reserve estimate.
Pressure-tolerant design (pressure-compensated, pressure-tolerant)Maritime: Building subsea equipment, such as batteries, to work flooded or oil-filled at ambient sea pressure instead of inside heavy pressure housings.
Price discoveryFinance: The process by which buyers and sellers arrive at a market price through trading. The price reflects the information, expectations and supply and demand present at that moment.
Price fixingFinance: An agreement among competitors to set, raise or hold prices instead of letting competition determine them. It is illegal under antitrust and competition laws in most jurisdictions.
Price torqueFinance: How much more a producer's earnings, cash flow or share price move than the price of the commodity it sells. Because much of a miner's cost is fixed, a 10% rise in the metal price can lift its margin by far more than 10%, and a fall cuts the margin just as sharply. (DataDeep Report on Gold Price Torque)
Price-to-sales and EV-to-sales ratiosFinance: Valuation multiples that compare a company to its revenue: market capitalisation divided by sales, or enterprise value (market capitalisation plus debt minus cash) divided by sales. They are used for companies without profits but ignore differences in margins.
Primary and secondary batteries (primary battery, secondary battery, rechargeable battery)Batteries: A primary battery is used once and discarded, like an alkaline battery. A secondary battery is rechargeable, like lithium-ion and lead-acid batteries.
Principal (contributed capital)Finance: The money actually put into an investment or account, before any gains or losses. In company accounts, contributed capital is the amount shareholders paid the company for its shares.
Printed-circuit heat exchanger (PCHE, PCHEs)Industry: A compact heat exchanger made from plates with chemically etched microchannels, diffusion-bonded into a solid block that withstands high pressure.
Private 5G (private LTE, private cellular)Computing: A dedicated cellular network owned or operated for one site, such as a factory, port or farm, giving reliable coverage and control.
Private market investmentsFinance: Investments in assets that do not trade on public exchanges, such as private equity, venture capital, private credit and private real estate. They are less liquid than listed securities and are valued far less often.
Process CO₂ captureSustainability: Catching the CO₂ that a plant releases during chemical conversion and storing it. For HVO, the capturable stream comes from decarboxylation, which strips oxygen as CO₂.
Process design kit (PDK, PDKs)Computing: The set of files and rules a foundry gives chip designers to describe its manufacturing process, so designs can be built correctly there.
Process heat (industrial heat)Batteries: Heat used in industrial production, such as drying, cooking, chemical reactions and steelmaking. It is a large and hard-to-electrify share of industrial energy use.
Process node (technology node, leading-edge node, mature node)Computing: A name for a generation of chip manufacturing technology, such as 3 nm or 2 nm. The number no longer matches any physical feature; it signals relative density and performance.
Process safety rules (PSM, Process Safety Management, RMP, Risk Management Program)Computing: The main US rules for hazardous chemical plants: OSHA's Process Safety Management standard protects workers, and EPA's Risk Management Program protects nearby communities.
Processing-in-memory (PIM, near-memory computing, compute-in-memory, in-memory computing)Computing: Placing compute logic inside or right next to memory so data does not have to travel to a separate processor. It targets the energy and delay of moving data.
Product slate (product yield)Industry: The mix of products a refinery makes from its crude. Complex refineries can shift the slate toward higher-value fuels.
Production certificateAerospace: Approval for a manufacturer to build copies of a certified design under an approved quality system, without the regulator inspecting each one from scratch.
Program of recordAerospace: A defense program with its own line in the budget and an approved acquisition plan, giving it multi-year funding. Becoming one is a key milestone for a defense startup's product.
Programmable logic controller (PLC, PLCs)Computing: A rugged industrial computer that controls machines and processes in real time.
Prohibited foreign entity (PFE, specified foreign entity, foreign-influenced entity)Batteries: A US tax-law category created in 2025 covering specified foreign entities, such as companies controlled by China, and foreign-influenced entities tied to them. It bars or limits clean-energy credits, including for batteries.
Proliferated LEO (pLEO, proliferated low Earth orbit)Aerospace: A military space architecture that spreads missions across many cheaper low Earth orbit satellites instead of a few large ones, so losing some does not break the system.
Proliferated Warfighter Space Architecture (PWSA)Aerospace: The US Space Development Agency's low Earth orbit constellation, with a transport layer for military data relay and a tracking layer for missile warning and tracking. It is fielded in tranches about two years apart.
Prompt injection (indirect prompt injection)Computing: An attack that hides instructions in text an AI model reads, such as a web page or document, to make it ignore its rules or leak data.
Propagation delay (signal delay)Aerospace: The time a signal takes to travel between two points at the speed of light. It sets a floor on latency: under 0.1 ms each way to a platform 20 km up and ≈120 ms each way to a geostationary satellite.
Propellant densification (propellant subcooling, subcooled propellant, densified propellant)Aerospace: Chilling propellants below their normal boiling point so more mass fits in the same tank. It adds performance but tightens the fueling timeline before launch.
Propellant depot (orbital depot)Aerospace: A spacecraft that stores propellant in orbit for other vehicles to draw on. Tanker flights fill it; departing vehicles refuel from it.
Proven and probable reserves (proven reserve, probable reserve, proved reserve, 2P reserves)Minerals: The two classes of mineral reserve: proven reserves come from measured resources, probable reserves from indicated resources, after mining, processing and economic factors are applied.
Prussian blue analogue (PBA, Prussian blue, Prussian white)Batteries: A family of low-cost cathode materials related to the pigment Prussian blue, with an open framework that lets sodium ions move easily. Prussian white is a sodium-rich form used in commercial cells.
PseudoliteAerospace: A ground- or air-based transmitter that broadcasts signals like those of navigation satellites, to add to or replace satellite positioning in a local area.
Pseudorange (pseudoranges)Maritime: The apparent distance to a navigation transmitter, from signal travel time, before receiver clock error is removed.
Public-key cryptography (RSA, elliptic-curve cryptography)Computing: Encryption that uses a public key to encrypt or verify and a private key to decrypt or sign. RSA and elliptic-curve cryptography, the current standards, are vulnerable to Shor's algorithm.
Pumped hydro storage (pumped storage, pumped hydro, PSH)Batteries: Storing energy by pumping water to an upper reservoir and releasing it through turbines when needed. Worldwide it holds far more stored energy than batteries do.
PX4 and ArduPilot (PX4, ArduPilot)Aerospace: Two widely used open-source autopilot software projects for drones. Many drone makers build on them instead of writing flight software from scratch.
Pyrometallurgy (pyrometallurgical recycling, smelting)Batteries: Recovering metals by smelting at high temperature. It handles mixed feed robustly and recovers nickel, cobalt and copper, but loses lithium and aluminum to slag and uses much energy.

Q

qLDPC codes (quantum low-density parity-check codes, qLDPC)Computing: Quantum low-density parity-check codes, error-correcting codes that could encode logical qubits with far fewer physical qubits than the surface code, but need longer-range connections.
Qualification and acceptance testing (qualification testing, acceptance testing)Aerospace: Qualification testing proves a design survives conditions beyond what it will see in service, often using dedicated test units. Acceptance testing checks each flight unit at milder levels before delivery.
Qualified person (QP, competent person)Minerals: An experienced, professionally registered geologist or engineer who must prepare or sign off on public resource and reserve disclosures. JORC uses the term competent person.
Quality Information Framework (QIF)Industry: An ANSI standard for exchanging measurement and inspection data, such as results from coordinate measuring machines, across software.
Quantization (int8 quantization, product quantization)Computing: Storing a model's numbers at lower precision, such as 8-bit integers instead of 32-bit floats, to cut memory and speed up computation at a small accuracy cost.
Quantum advantage (quantum supremacy, quantum utility)Computing: When a quantum computer solves a useful problem faster, cheaper or better than the best classical methods. Quantum supremacy refers to beating classical computers on any task, useful or not.
Quantum annealing (quantum annealer)Computing: A type of quantum computing that solves optimization problems by letting a system of qubits settle into its lowest-energy state. It is limited to certain problem types and is not a universal quantum computer.
Quantum error correction (QEC, error correction)Computing: Encoding one logical qubit across many physical qubits so errors can be detected and fixed during computation. It is required for large, reliable quantum computers.
Quantum gate (two-qubit gate, CZ gate, quantum circuit, circuit depth)Computing: A basic operation on one or more qubits, analogous to a logic gate in classical computing. Algorithms are built as circuits of gates.
Quantum inertial sensors (quantum navigation, quantum inertial navigation, quantum gyroscope, quantum accelerometer)Maritime: Accelerometers, gyroscopes and gravimeters based on cold-atom interferometry, aimed at navigating for long periods without satellite fixes.
Quantum key distribution (QKD)Computing: Sharing encryption keys using quantum states of light, so any eavesdropping disturbs the signal and is detected. It needs special hardware and distance-limited links.
Quantum processing unit (QPU)Computing: The chip or system that holds and controls qubits, the quantum counterpart of a CPU or GPU.
Quantum volumeComputing: A single-number benchmark of a quantum computer's capability that combines qubit count, fidelity and connectivity. Higher is better.
Quantum-inspired algorithm (quantum-inspired)Computing: A classical algorithm that borrows ideas from quantum computing, such as annealing or tensor networks, and runs on ordinary hardware.
Qubit (qubits, quantum bit, physical qubit)Computing: The basic unit of quantum information, which can be in a blend of 0 and 1 at once. Physical qubits are error-prone; logical qubits combine many physical ones to correct errors.
Qubit modalities (trapped-ion, trapped ion, neutral-atom, neutral atom, photonic qubit, spin qubit)Computing: The main physical ways to build qubits: superconducting circuits, trapped ions held by electric fields, neutral atoms held by lasers, photons, and electron spins in semiconductors. Each trades speed, fidelity and scalability.
QUBO (quadratic unconstrained binary optimization)Computing: Quadratic unconstrained binary optimization, a standard way to write optimization problems as yes-no variables with pairwise costs. It is the input format for quantum annealers and many solvers.
Quenchant injection (electrophilic injection)Aerospace: A blackout-mitigation method that sprays water or electron-capturing chemicals into the plasma around a reentry vehicle, cutting electron density so radio signals can pass.

R

Rack density (kW per rack)Computing: The power drawn by one rack of servers, in kilowatts. AI racks draw several times more than traditional racks, which pushes data centers to liquid cooling.
Radiation efficiencyAerospace: The share of power fed into an antenna that is actually radiated, rather than lost as heat. Metal antennas exceed 99%; lossy conductors such as plasma radiate less.
Radiation hardening (radiation-hardened, rad-hard, radiation-tolerant, single-event effects, SEE, total ionizing dose, TID)Computing: Designing or screening chips to survive radiation in space or near reactors. Single-event effects are glitches from individual particles; total ionizing dose is damage that builds up over time.
Radio Attenuation Measurement program (RAM-C, RAM program)Aerospace: A NASA flight program of the 1960s that flew instrumented reentry vehicles to measure plasma density and radio blackout. Its data remain a standard reference in blackout research.
Radio frequency bands (L-band, S-band, C-band, X-band, Ku-band, K-band, Ka-band, V-band, VHF, UHF)Aerospace: Letter names for ranges of radio frequencies. Higher bands carry more data and allow smaller antennas but suffer more from rain and atmospheric loss. The ranges below follow the IEEE convention; satellite usage can differ slightly, for example satellite C-band starts at ≈3.7 GHz. See the table
RadomeAerospace: A weatherproof cover over an antenna or radar that lets radio waves pass with little loss. On hypersonic vehicles radomes must also survive extreme heat.
RAGAS (Retrieval-Augmented Generation Assessment)Computing: Retrieval-augmented generation assessment, an open-source framework that scores RAG systems on measures such as faithfulness to sources and answer relevance.
Rain fade (rain attenuation)Aerospace: Weakening of radio signals by rain, which grows sharply at higher frequencies such as Ku- and Ka-band. Satellite links carry extra margin to ride through it.
RamjetAerospace: An air-breathing engine with no major moving parts that uses the vehicle's own speed to compress incoming air. It cannot work from a standstill and needs a booster to reach ≈Mach 2–3 first. Combustion happens at subsonic speed.
Randomized benchmarkingComputing: A standard method for measuring quantum gate error rates by running random gate sequences and seeing how fast results degrade.
Rankine and Brayton cycles (Rankine cycle, Brayton cycle)Batteries: The two main heat-engine cycles for generating power. The Rankine cycle boils water into steam to drive a turbine; the Brayton cycle heats compressed gas, as in gas turbines.
Rare earth elements (rare earths, REE, REEs, rare earth metals, lanthanides)Minerals: The 15 lanthanides plus scandium and yttrium, 17 chemically similar metals. They are not especially rare in the crust but are seldom concentrated and hard to separate.
Rare earth ore minerals (bastnäsite, bastnaesite, monazite, xenotime, eudialyte, allanite)Minerals: The main minerals mined for rare earths. Bastnäsite and monazite carry mostly light rare earths; xenotime carries heavy ones; eudialyte carries both with zirconium. Monazite is often radioactive from thorium.
Rare earth oxide (REO, TREO, total rare earth oxide, HREO, heavy rare earth oxide)Minerals: The standard form in which rare earth content and output are measured and traded. TREO is total rare earth oxide; HREO is the heavy share.
Rare earth separation (separation and refining, rare earth refining, separated rare earths)Minerals: Splitting a mixed rare earth solution into individual high-purity oxides, usually by solvent extraction across hundreds of mixer-settler stages. It is the step China most dominates.
Rare-earth-free magnet (iron nitride magnet, iron nitride)Minerals: Magnet materials under development that avoid rare earths, such as iron nitride. None yet matches NdFeB at scale.
Rayleigh criterion (k1, k1 factor, Rayleigh equation)Computing: The formula for the smallest printable half-pitch: k1 × wavelength ÷ numerical aperture. Shorter wavelength, higher numerical aperture or lower k1 all shrink features; k1 cannot go below 0.25 in one exposure.
ReachstackerIndustry: A heavy vehicle with a telescopic boom that lifts and stacks containers, used where cranes are not available.
Reaction wheel (momentum wheel)Aerospace: A flywheel inside a spacecraft that is spun faster or slower to turn the spacecraft the opposite way, letting it point without using propellant. Most are driven by permanent-magnet motors.
Realized gainFinance: A profit locked in by selling an investment for more than its cost basis. In most tax systems a sale that realizes a gain is a taxable event.
Reasonable country of origin inquiry (RCOI)Minerals: The good-faith check a company must run under the US conflict minerals rule to learn where its 3TG came from.
RebalanceFinance: The scheduled date on which a portfolio's holdings are recomputed and trades are assumed to occur.
Reciprocal rank fusion (RRF)Computing: A simple way to merge ranked lists from different search methods by summing scores based on each item's rank.
Recirculating aquaculture system (RAS, recirculating aquaculture)Maritime: A land-based fish farm that filters and reuses most of its water, controlling temperature, oxygen and waste, at the cost of high energy use and capital.
Recompression Brayton cycle (RCBC, recompression cycle)Industry: The leading supercritical CO₂ cycle layout, which splits the flow between two compressors to cut heat lost in cooling and raise efficiency.
Reconfigurable antenna (frequency-agile antenna, reconfigurable aperture)Aerospace: An antenna whose frequency, pattern or polarization can be changed in use, letting one aperture do several jobs.
Reconfigurable intelligent surface (RIS)Aerospace: A metasurface whose elements can be switched electronically to redirect radio signals, for example around obstacles in a wireless network.
Record of decision (ROD)Aerospace: The formal document in which a US agency states its decision after an environmental review, and the reasons for it.
Recovery rate (material recovery rate)Batteries: The share of a given metal in recycling feed that is recovered in usable form. Recyclers often quote rates of 95% or more for nickel and cobalt; lithium rates are usually lower.
Recuperator (recuperators)Industry: A heat exchanger that passes heat from a cycle's hot exhaust to the cooler fluid entering the heater, raising efficiency. Supercritical CO₂ cycles depend on large, efficient recuperators.
Recycled content (recycled content minimums)Batteries: The share of a product's material that comes from recycling. EU rules require new industrial and EV batteries to contain set minimums of recycled cobalt, lithium, nickel and lead from August 2031. See the table
Recycling efficiencyBatteries: Under EU battery rules, the share by weight of a waste battery that a recycling process turns into usable output. For lithium-based batteries the target was 65% by the end of 2025.
Recycling rates (end-of-life recycling rate, EOL recycling rate, recycling input rate, secondary supply)Minerals: The end-of-life recycling rate is the share of metal in discarded products that is recovered. The recycling input rate is the share of supply that comes from scrap of any kind.
RED (Renewable Energy Directive)Sustainability: The EU's main law for renewable energy, first adopted in 2009 and recast as RED II in 2018 and amended as RED III in 2023. It sets the EU lifecycle method that most European HVO claims rely on.
Redox reaction (redox, oxidation and reduction)Batteries: A chemical reaction in which one substance loses electrons (oxidation) and another gains them (reduction). Every battery's discharge is a controlled redox reaction.
Reefer container (reefer, reefers, refrigerated container)Maritime: A refrigerated shipping container that needs electrical power aboard ship and at the terminal to keep cargo cold.
Reentry (re-entry, atmospheric entry)Aerospace: The return of a spacecraft or rocket stage from space through the atmosphere. Air compressed ahead of the vehicle causes intense heating and, at high speed, forms a layer of ionized gas around it.
Reentry blackout (communications blackout, radio blackout, plasma blackout)Aerospace: The loss of radio contact with a vehicle during reentry or hypersonic flight, because the plasma sheath blocks signals below a critical frequency. It typically lasts minutes. Higher radio frequencies, vehicle shaping and injected chemicals can shorten it.
Reentry capsule (return capsule)Aerospace: A small spacecraft built to survive reentry and bring cargo or crew back to Earth, usually slowed by a heat shield and parachutes. Uncrewed capsules return experiments and products made in orbit.
Refined products (naphtha, premium motor spirit, PMS, automotive gas oil, AGO, gasoil, Jet A-1)Industry: The main fuels and feedstocks refineries make. Naphtha feeds petrochemicals and gasoline blending; gasoline is sold in Nigeria and elsewhere as premium motor spirit; diesel is sold as automotive gas oil.
Refinery residue (residuum, reduced crude, resid, vacuum residue)Industry: The heavy fraction left at the bottom of crude distillation, which must be cracked, coked or sold as fuel oil.
Refinery turnaround (turnaround, planned shutdown)Industry: A planned shutdown of a refinery or unit for inspection, maintenance and upgrades, usually every few years.
Refractory metals (refractory metal)Minerals: Metals with very high melting points and hardness: chiefly tungsten, molybdenum, tantalum, niobium and rhenium.
RefurbishmentAerospace: The work done between flights of reusable rocket hardware: inspecting engines, replacing worn parts and retesting. Its cost and duration decide how much reuse actually saves.
Regenerative coolingAerospace: Cooling a rocket engine by running cold propellant through channels in the chamber and nozzle walls before it is burned. The heat it picks up goes back into combustion instead of being wasted.
Regolith simulant (lunar simulant, JSC-1A, highland simulant)Minerals: Earth-made material engineered to mimic lunar or Martian soil, used to test excavation and processing equipment.
Regolith sintering (sintered regolith)Minerals: Heating regolith until grains fuse, to make bricks, landing pads or printed structures without binders from Earth.
Regulatory complianceFinance: Meeting the laws, regulations and standards that apply to a business, from securities disclosure to environmental permits. Failures can bring fines, restrictions on operations or reputational damage.
Reinforcement learning (RL)Computing: Training a system by trial and error, rewarding actions that lead to good outcomes. It powers game-playing systems and is used to refine language models.
Reinvested profitsFinance: Earnings a company puts back into the business, for example into equipment, research or acquisitions, instead of distributing them. They accumulate in retained earnings.
Remanence (remanent magnetization)Minerals: The magnetic flux density a magnet keeps after the magnetizing field is removed, measured in tesla.
Remote ID (Remote Identification)Aerospace: A requirement for most drones flown in the US to broadcast their identity and location in flight, so authorities and the public can identify them. It is set out in 14 CFR Part 89.
Remotely operated vehicle (ROV, work-class ROV)Computing: An uncrewed underwater robot controlled from a ship through a tether, used for cable repair, inspection and seabed work.
RenderingSustainability: Cooking animal by-products from slaughterhouses to separate fat (tallow) from protein meal and water. Renderers control much of the lowest-carbon HVO feedstock.
Replicator (Replicator initiative)Aerospace: A US Defense Department initiative announced in 2023 to field thousands of cheap, attritable autonomous systems within about two years. In November 2025 its portfolio moved to the Defense Autonomous Warfare Group.
Reranking (reranker, cross-encoder)Computing: A second retrieval step in which a more accurate model reorders the top search results before they reach the language model.
Rescue Agreement, Liability Convention and Registration Convention (Rescue Agreement, Liability Convention, Registration Convention)Aerospace: UN treaties that build on the Outer Space Treaty. The 1968 Rescue Agreement covers aid to astronauts, the 1972 Liability Convention makes launching states liable for damage, and the 1975 Registration Convention requires registering space objects.
Reserve-to-production ratio (R/P ratio, R/P, reserve life)Minerals: Current reserves divided by annual production, giving years of output at today's rate. Reserves grow with exploration and prices, so it is not an exhaustion date.
Reservoir computingComputing: A machine learning approach that feeds inputs into a fixed, complex dynamic system and trains only a simple readout layer. Physical systems such as optics can serve as the reservoir.
Reshoring and nearshoring (reshoring, nearshoring, onshoring, friend-shoring, friendshoring)Industry: Moving production back to the home country (reshoring), to nearby countries (nearshoring) or to allied countries (friend-shoring), to cut supply risk and lead times.
Residual stressIndustry: Stress locked inside a part after manufacture, from uneven heating and cooling. In printed metal it can cause distortion and cracking unless relieved by heat treatment.
ResidueSustainability: A material produced incidentally by a process that was not aimed at making it, such as tallow or tall oil. Residues sit between wastes and co-products and are often assigned zero upstream emissions in attributional rules.
Residue supply ceilingSustainability: The fixed upper limit on waste and residue supply, set by how much cooking, slaughter or refining occurs rather than by fuel prices. Extra fuel demand beyond it is met by crop oils.
Resource confidence categories (measured resource, indicated resource, inferred resource, measured and indicated, M&I)Minerals: Mineral resources are classed by geological confidence: measured is highest, indicated next and inferred lowest. Only measured and indicated resources can be converted to reserves.
Resource nationalismMinerals: Government moves to take a larger share of mineral wealth, through higher royalties, state ownership, export bans or local processing rules.
Responsible Minerals Initiative (RMI, Responsible Minerals Assurance Process, RMAP, Conflict Minerals Reporting Template, CMRT)Minerals: An industry body that audits smelters and refiners against responsible sourcing standards and publishes the Conflict Minerals Reporting Template.
Responsive launch (tactically responsive space)Aerospace: The ability to launch a satellite on short notice, in days or hours rather than months. Militaries want it to replace lost satellites quickly or respond to a crisis.
Restartable engine (engine relight, relight, in-space restart)Aerospace: An engine that can shut down and fire again in flight. Upper stages need restarts to reach high or multiple orbits; reusable boosters need them to land.
Retained earningsFinance: The cumulative profits a company has kept rather than paid out as dividends. They appear in shareholders' equity on the balance sheet.
Retrieval metrics (nDCG, nDCG@10, top-k, retrieval recall)Computing: Measures of search quality. Recall is the share of relevant items found; precision is the share of results that are relevant; nDCG also rewards ranking relevant items near the top.
Retrieval-augmented generation (RAG, GraphRAG, agentic RAG)Computing: A method that searches a document collection for relevant passages and gives them to a language model to ground its answer. It lets models use private or recent information and cite sources.
Return to flightAerospace: The first launch after a failure or grounding, once investigators and regulators accept the fixes. Its timing shows how long a vehicle or pad was out of service.
Return to launch site (RTLS)Aerospace: A booster recovery method in which the first stage turns around after separation and flies back to land near its launch pad. It costs more propellant than landing at sea, which reduces payload.
Reusable launch vehicle (reusable rocket, reusability, RLV)Aerospace: A rocket built so that major parts, usually the first stage and sometimes the fairing, can be recovered and flown again. Reuse spreads build cost over many flights, but flown hardware still needs inspection and refurbishment. Fully reusable designs also recover the upper stage.
Revenue recognitionFinance: The rule that decides when a company records revenue, which is when it delivers the goods or services it promised rather than when cash arrives. ASC 606 and IFRS 15 set this out as a five-step model built on performance obligations and the transfer of control.
Reversible computingComputing: Computing designed so that operations can be undone without erasing information, which in principle avoids the Landauer energy cost.
Reynolds numberAerospace: A dimensionless ratio of inertial to viscous forces in a flow. Small aircraft and subscale models fly at low Reynolds numbers, so their aerodynamics may not scale up cleanly.
RFS (Renewable Fuel Standard)Sustainability: The U.S. federal program, run by the EPA, that mandates annual volumes of renewable fuel in the transport supply. Its lifecycle analysis includes ILUC. Its 2018 grain sorghum oil pathway was the first U.S. regulatory use of displacement emissions.
RheniumMinerals: A very rare metal recovered from molybdenum concentrates of porphyry copper ores, used in jet-engine superalloys and refinery catalysts.
Ride-throughBatteries: The ability of equipment to keep running through a brief power dip or outage, often supplied by batteries or flywheels until backup generation starts.
RideshareAerospace: A launch in which many small satellites from different customers share one rocket and split its cost. It is cheap per kilogram, but each customer accepts the shared orbit and schedule.
Risk managementFinance: The practice of identifying, measuring and limiting exposures that could cause losses. In a portfolio it uses tools such as position sizing, diversification, hedging and loss limits.
Risk-return tradeoffFinance: The principle that a higher expected return generally comes with more risk of loss or volatility. How much risk suits an investor depends on their goals, time horizon and tolerance for losses.
RLS trade-off (RLS triangle, resolution, line-edge roughness and sensitivity)Computing: The tension between resolution, line-edge roughness and sensitivity in photoresists: improving one usually worsens another.
ROADM (reconfigurable optical add-drop multiplexer)Computing: Reconfigurable optical add-drop multiplexer, a network node that adds, drops or routes individual wavelengths remotely without converting them to electrical signals.
Robot density (IFR)Industry: The number of industrial robots per 10,000 manufacturing employees, the International Federation of Robotics' standard measure of how automated a country's industry is.
Rocking-chair battery (rocking chair intercalation)Batteries: A battery in which ions shuttle back and forth between two intercalation electrodes during charge and discharge. Lithium-ion and sodium-ion cells both work this way.
Room-and-pillar mining (room and pillar)Minerals: An underground method that mines ore in rooms and leaves pillars of rock to hold up the roof, suited to flat-lying deposits.
Rotary kiln-electric furnace (RKEF, nickel pig iron, NPI, ferronickel)Minerals: A smelting route that dries and reduces nickel laterite in a kiln, then melts it in an electric furnace to make ferronickel or nickel pig iron.
Rotational kinetic energy (moment of inertia, E = ½Iω²)Batteries: The energy stored in a spinning body: half its moment of inertia times its angular speed squared. Doubling a flywheel's speed stores four times the energy, so rotor strength limits capacity.
RotorcraftAerospace: An aircraft that gets its lift from rotating blades, such as a helicopter or gyroplane. US rules certify rotorcraft separately from airplanes.
Rotterdam in-warehouse price (Rotterdam price, in-warehouse Rotterdam)Minerals: A European benchmark for minor metals and concentrates delivered into a Rotterdam warehouse, used for tungsten, antimony and others.
Round-trip efficiency (RTE)Batteries: The share of energy put into storage that comes back out. Lithium-ion batteries return ≈85–95%; pumped hydro ≈70–80%; heat stores converted back to electricity far less.
Route survey (cable route survey, marine route survey)Maritime: A pre-installation survey of the seabed corridor a cable or pipeline will follow, using bathymetry, sub-bottom profiling and sampling.
Rubble-pile asteroid (rubble pile)Minerals: An asteroid made of loose rock held together by weak gravity, which makes anchoring and digging difficult.
Run-of-mine ore (ROM, ROM pad, run of mine)Minerals: Ore as it comes from the mine, before crushing or sorting. The ROM pad is where it is stockpiled ahead of the plant.

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S-K 1300 (Regulation S-K Subpart 1300, SK-1300, S-K-1300, technical report summary, TRS)Minerals: The US Securities and Exchange Commission rule for disclosing mining properties, in force since 2021. It requires a qualified person's technical report summary for material properties.
SAE J2464Batteries: An SAE practice for abuse-testing electric-vehicle batteries, such as crush, penetration, overcharge and fire exposure.
SamariumMinerals: A light rare earth used mainly in samarium-cobalt magnets, typically recovered as a minor by-product of mixed rare earth processing.
Samarium-cobalt magnet (SmCo, SmCo5, SmCo₅, Sm2Co17, Sm₂Co₁₇, samarium cobalt)Minerals: A rare earth magnet that keeps its strength at higher temperatures and resists corrosion and radiation better than NdFeB. It is used in defense, aerospace and high-heat motors.
Sample stages (A-sample, B-sample, C-sample, A-samples, B-samples, C-samples)Batteries: The automotive qualification stages for new cells. A-samples are early prototypes, B-samples are near-final designs from pilot lines, and C-samples come from production-intent lines for vehicle validation.
Sand battery (sand-based thermal storage)Batteries: A marketing name for thermal storage that heats sand or crushed rock with electricity to several hundred degrees Celsius and later releases the heat. It mainly supplies district heating and industrial heat.
Saturation diving (saturation diver, sat diving)Maritime: A deep-diving method in which divers live under pressure in a chamber for days or weeks. Their tissues become saturated with gas, so they decompress only once, at the end.
SC-VTOL (Special Condition VTOL)Aerospace: EASA's special condition setting airworthiness requirements for small vertical-takeoff aircraft with distributed lift and thrust, such as eVTOLs. Aircraft in commercial passenger service must achieve continued safe flight and landing after failures.
SCADA (supervisory control and data acquisition)Computing: Supervisory control and data acquisition, software that gathers data from remote equipment and lets operators monitor and control it.
Scramjet (supersonic combustion ramjet)Aerospace: A ramjet in which air stays supersonic through the combustor. It is the leading air-breathing option above ≈Mach 5–6, but keeping a flame lit in supersonic flow is very hard.
Scrap rateBatteries: The share of material or cells discarded during production. High scrap rates raise costs and supply manufacturing scrap to recyclers.
Sea state (Douglas sea scale)Maritime: A scale describing wave and swell conditions, from calm to phenomenal. It limits when vessels, vehicles and divers can be launched and recovered.
Seabed mining moratorium (moratorium, precautionary pause)Minerals: Calls by governments, scientists and companies for a pause on deep-sea mining until its environmental effects are better understood.
Seabed warfare (seabed operations)Maritime: Military operations on or near the seafloor, including attacking or protecting cables, pipelines and sensors.
Seafloor massive sulfides (SMS, polymetallic sulphides, polymetallic sulfides, seafloor massive sulphides)Minerals: Copper, zinc, gold and silver deposits built up around hydrothermal vents on mid-ocean ridges.
Seaweed farming (kelp farming, seaweed cultivation, kelp, macroalgae)Maritime: Growing kelp and other seaweeds on ropes or nets in the sea for food, feed, fertilizer and materials. It needs no freshwater, feed or fertilizer.
Second-life battery (second life, second-life)Batteries: A retired electric-vehicle battery reused in a less demanding role, such as stationary storage, before recycling. Testing, warranties and mixed pack designs limit the market.
Section 30D (30D, clean vehicle credit)Batteries: The US clean vehicle tax credit of up to $7,500 for new electric vehicles, with battery sourcing rules. The 2025 OBBBA law ended it for vehicles acquired after 30 September 2025.
Section 45Q (45Q, carbon oxide sequestration credit)Industry: The US tax credit for capturing and storing CO₂. Since the 2025 OBBBA law it pays up to $85 per tonne for point-source capture and $180 for direct air capture. Stored and used CO₂, including for oil recovery, now earn the same rate.
Section 45X (45X, advanced manufacturing production credit)Batteries: The US advanced manufacturing production credit. For batteries it pays $35 per kWh of cells and $10 per kWh of modules made and sold in the US, phasing down from 2030 to zero after 2032.
Section 45Z (clean fuel production credit)Sustainability: A U.S. tax credit created by the Inflation Reduction Act of 2022 for low-emission transport fuel produced from 2025, scaled by carbon intensity. As amended in 2025, it uses the 45ZCF-GREET model, excludes ILUC for fuel produced after 2025 and restricts feedstocks to North America.
Section 48D (48D, advanced manufacturing investment credit)Computing: The US advanced manufacturing investment credit for building semiconductor fabs and tool plants, created by the CHIPS Act. The 2025 OBBBA law raised it from 25% to 35% for property placed in service after 2025.
Section 48E (48E, clean electricity investment credit, investment tax credit, ITC)Batteries: The US clean electricity investment tax credit, which also covers energy storage technology. Since 2025 it carries prohibited foreign entity and material assistance limits.
Section 232 (Section 232 tariffs, 232 tariffs)Industry: A US law, from the Trade Expansion Act of 1962, that lets the president restrict imports that threaten national security. Its steel and aluminum tariffs, first set in 2018, were raised to 50% in June 2025.
Section 301 (Section 301 tariffs, USTR)Industry: A US trade law that lets the US Trade Representative act against unfair foreign trade practices, the basis for the tariffs placed on many Chinese goods from 2018.
Secure bootComputing: A startup process that checks a device's software is genuine and unaltered before running it.
Sediment plume (plume, discharge plume, midwater plume, turbidity current)Minerals: A cloud of fine sediment stirred up by seabed mining or discharged from the ship, which can drift far and smother seafloor life.
Selective catalytic reduction (SCR, NOx abatement)Industry: Removing nitrogen oxides from exhaust by reacting them with ammonia or urea over a catalyst, turning them into nitrogen and water.
Self-discharge (standby losses, self-discharge rate)Batteries: The gradual loss of stored energy while a battery or other storage device sits unused. Lithium-ion cells lose a few percent a month; flywheels and thermal stores can lose energy far faster.
Self-playComputing: A reinforcement learning method in which a system improves by competing against copies of itself, without human examples.
Semi-fuel cell (metal-water semi-fuel cell, aluminum-seawater battery)Maritime: An underwater power source in which a metal such as aluminum reacts with seawater to make electricity, giving long endurance without carrying an oxidizer.
Semi-solid battery (semi-solid-state, quasi-solid, hybrid solid-liquid battery, solid-liquid battery)Batteries: A battery that mixes solid electrolyte with a smaller amount of liquid or gel electrolyte. A December 2025 draft Chinese national standard drops the term and calls such cells hybrid solid-liquid batteries.
Sensible heat storage (sensible heat)Batteries: Storing heat by raising a material's temperature without changing its state. The heat stored equals mass × specific heat × temperature rise.
Sensor fusionAerospace: Combining data from several sensors, such as radar, cameras and radio receivers, into one picture more accurate than any single sensor gives.
Separator (separator film)Batteries: A thin porous film, usually polyethylene or polypropylene, that keeps a cell's electrodes from touching while letting ions pass through. A separator failure can cause an internal short circuit.
SerDes (serializer/deserializer)Computing: Serializer/deserializer, the circuit that converts parallel data into a fast serial stream for transmission and back. Lane speeds such as 200 Gb/s set chip-to-chip bandwidth.
Service ceilingAerospace: The highest altitude at which an aircraft can still climb at a small set rate, commonly 100 ft per minute. It marks the practical top of its flight envelope.
Seveso III Directive (Seveso III, Directive 2012/18/EU)Computing: Directive 2012/18/EU, the EU law on preventing and limiting major accidents at sites that store dangerous chemicals.
SFAR No. 120 (Part 194, Special Federal Aviation Regulation No. 120, powered-lift SFAR)Aerospace: The FAA's special rule for powered-lift pilot certification, training and operations, codified as 14 CFR Part 194. Published in November 2024, it took effect in January 2025 and runs for 10 years.
Sharpe ratioFinance: Annualised excess return over the risk-free rate divided by annualised standard deviation of returns. Highly sensitive to sample length.
Ship stability (stability margin, metacentric height, intact stability)Maritime: A ship's ability to return upright after heeling, set by where its center of gravity sits relative to its buoyancy. Heavy loads carried high, such as deck batteries, reduce the margin.
Ship-to-shore crane (STS crane, STS, quay crane)Industry: The large quay crane that lifts containers between ships and the terminal. Its moves per hour set how fast a ship is turned around.
Shor's algorithm (Shor)Computing: A quantum algorithm that factors large numbers efficiently, which would break RSA and elliptic-curve encryption once large fault-tolerant quantum computers exist.
Shore power (cold ironing, onshore power supply)Batteries: Supplying electricity from land to a docked ship so it can switch off its engines. It cuts port emissions but needs large grid connections at the berth.
Shot noise (photon shot noise, Poisson noise)Computing: Random variation in the number of photons or electrons arriving, which grows relatively larger as doses shrink. It drives stochastic defects in lithography and noise in optical detectors.
Significant wave height (Hs, SWH)Maritime: The average height of the highest third of waves in a sea state, the standard measure of wave conditions for design and operations.
Silicon anode (silicon-anode, silicon-carbon anode, silicon composite anode)Batteries: An anode that uses silicon, alone or blended with graphite, because silicon can hold about ten times more lithium per gram. Silicon swells up to ≈300% when charged, which cracks particles and shortens life.
Silicon photonics (SiPh)Computing: Building optical components, such as waveguides, modulators and detectors, on silicon wafers using chip-industry processes. It makes optical links cheap enough for data centers.
Silicon-on-insulator (SOI, FD-SOI, fully depleted SOI, buried oxide)Computing: A wafer with a thin silicon layer on top of an insulating oxide layer. It reduces leakage in chips and is the standard substrate for silicon photonics.
Sintered and bonded magnets (sintered magnet, sintered NdFeB, bonded magnet, bonded NdFeB, hot-deformed magnet)Minerals: Sintered magnets are pressed from powder and fused in a furnace, giving the highest strength. Bonded magnets mix powder with a binder for complex shapes at lower strength.
Sintering (debinding)Industry: Bonding powder particles into a solid by heating below the melting point. Binder-jetted metal parts and ceramics are densified this way.
Skarn (skarn deposit, garnet skarn, contact metasomatic deposit)Minerals: A rock formed where hot fluids from an intrusion react with limestone or similar rock. Skarns host many tungsten, copper and zinc deposits.
SkewnessFinance: A measure of how lopsided a return distribution is. Negative skew means occasional large losses with more frequent small gains; positive skew means occasional large gains.
SLI battery (starting, lighting and ignition battery, starter battery)Batteries: A battery that powers starting, lighting and ignition in combustion vehicles, traditionally lead-acid. EU battery rules treat it as its own category.
Small modular reactor (SMR, SMRs, small modular reactors)Industry: A nuclear fission reactor of up to ≈300 MWe, designed to be built largely in factories and installed in modules. Smaller size aims to cut cost and construction risk.
Smallsat (small satellite)Aerospace: A small satellite, typically light enough to share a rocket with many others. Definitions vary widely: NASA often uses 180 kg as the upper limit, while some industry counts go up to 1,200 kg.
Smart CutComputing: A layer-transfer process that splits a thin crystal layer from a donor wafer using implanted hydrogen and bonds it to another wafer. It is the main way silicon-on-insulator wafers are made.
Smelter (smelting plant)Industry: A plant that extracts metal from ore or concentrate by heating it in furnaces, often producing an intermediate such as matte or crude metal for refining.
Soda ash (sodium carbonate, Solvay process)Batteries: Sodium carbonate, a common industrial chemical made mostly by the Solvay process or mined as trona. It is the main sodium source for sodium-ion cathodes.
Sodium-cooled fast reactor (SFR, fast reactor)Industry: A reactor cooled by liquid sodium that uses fast neutrons, which lets it burn more of its fuel and some long-lived waste.
Sodium-ion battery (Na-ion, SIB, sodium-ion)Batteries: A rechargeable battery that uses sodium ions instead of lithium. Sodium is abundant and cheap, and cells work well in the cold, but energy density is lower than LFP.
Soft magnetic material (soft magnet, soft magnetic composite, SMC)Industry: A material that magnetizes and demagnetizes easily with little loss, used in transformer, motor and inductor cores, unlike permanent magnets.
Software as a service (SaaS)Computing: Software delivered over the internet on subscription instead of installed and owned. Customers pay per user or per use.
Soil carbon (soil organic carbon, SOC)Sustainability: Carbon stored in soil as decomposed plant and microbial material. Practices such as reduced tillage and cover crops can raise it, but gains are reversible, saturate over time and are hard to verify.
Soil N₂O (direct and indirect)Sustainability: Nitrous oxide emitted from fertilized soil. Direct emissions come from the field itself; indirect emissions arise after nitrogen escapes as ammonia gas (volatilization) or dissolves into water (leaching) and is converted elsewhere.
Soil-carbon creditSustainability: A reduction in reported fuel intensity claimed for farming practices that build soil carbon. U.S. policy now lets such practices feed into Section 45Z through USDA's feedstock carbon-intensity framework from 29 July 2026.
Solid electrolyte (solid-state electrolyte, inorganic electrolyte)Batteries: A solid material that conducts ions between a battery's electrodes. The main families are sulfides, oxides, polymers and halides, each trading conductivity against stability and ease of manufacture.
Solid electrolyte interphase (SEI, SEI layer)Batteries: A thin layer that forms on the anode surface during a cell's first charges, as electrolyte breaks down. A stable layer protects the cell; continued growth consumes lithium and causes capacity loss.
Solid rocket motor (SRM, solid rocket booster, SRB)Aerospace: A rocket motor whose fuel and oxidizer are mixed into a rubbery solid cast inside the casing. It is simple, storable and powerful, but cannot be shut down or throttled once lit. Missiles and strap-on boosters use them widely.
Solid-state battery (SSB, solid-state lithium battery, SSLB, all-solid-state battery, ASSB)Batteries: A battery that uses a solid electrolyte instead of a flammable liquid one. It could allow lithium-metal anodes, higher energy density and better safety, but making large cells cheaply remains unproven.
Solid-state drive (SSD, SSDs)Computing: A storage drive built from flash memory with no moving parts. It is much faster than a hard drive and is the main storage in data centers for active data.
SolvencyFinance: The ability to meet long-term obligations as they come due. A quick check is shareholders' equity (assets minus liabilities); solvency ratios such as debt to assets and interest coverage examine it in more detail.
Solvent extraction (SX)Batteries: Separating dissolved metals by mixing a water solution with an organic liquid that selectively picks up one metal. It is used both in battery recycling and in rare earth refining.
Sonar (passive sonar, active sonar, SONAR)Maritime: Sound navigation and ranging, the use of underwater sound to detect, locate and identify objects. Passive sonar only listens; active sonar sends pings and listens for echoes.
Sonobuoy (sonobuoys)Maritime: An expendable buoy dropped from aircraft or ships that listens with a hydrophone and radios the sounds back for anti-submarine search.
Sortino ratioFinance: Annualised excess return divided by downside deviation only, ignoring volatility from positive returns.
Sound speed profile (SSP, sound velocity profile, sound-speed gradient)Maritime: How the speed of sound in seawater changes with depth, set by temperature, pressure and salinity. It bends sound paths and creates shadow zones and long-range channels.
Space Act AgreementAerospace: A flexible NASA agreement, outside standard procurement rules, used to partner with companies on technology development and commercial services.
Space Development Agency (SDA)Aerospace: A US Space Force agency that fields proliferated low Earth orbit constellations quickly, in roughly two-year tranches, starting with data transport and missile tracking layers.
Space Launch System (SLS)Aerospace: NASA's super heavy-lift rocket for the Artemis program, built largely from Space Shuttle-derived engines and boosters. It is expendable, and auditors have criticized its cost per launch.
Space Systems Command (SSC)Aerospace: The US Space Force field command that develops and buys space systems and launch services, including National Security Space Launch.
Space traffic managementAerospace: The tracking, rules and coordination needed to keep objects in orbit from colliding as satellite numbers grow.
Spacecraft bus (satellite bus)Aerospace: The standard platform of a satellite that supplies power, propulsion, pointing, thermal control and communications. The mission's instruments, called the payload, are mounted on it.
Special class (21.17(b), special-class aircraft)Aerospace: A US type certification path under 14 CFR 21.17(b) for aircraft that do not fit existing airworthiness standards, such as powered-lift. The FAA writes tailored criteria for each design, drawn from existing rules.
Special conditionsAerospace: Additional safety standards a regulator issues when a design has novel features that existing rules do not cover, such as electric propulsion.
Specific capacity (mAh/g, gravimetric capacity)Batteries: The charge an electrode material can store per unit mass, in milliampere-hours per gram (mAh/g). It is the main yardstick for comparing anode and cathode materials.
Specific energy (gravimetric energy density, Wh/kg)Batteries: Energy stored per unit mass, in watt-hours per kilogram (Wh/kg), at cell or pack level. It sets range in vehicles and endurance in aircraft and drones.
Specific impulse (Isp)Aerospace: A measure of rocket engine efficiency: thrust produced per unit of propellant used per second, given in seconds. Higher is better. Hydrogen engines reach ≈450 s in vacuum; kerosene and methane engines sit lower, ≈300–380 s.
Specific power (power density, W/kg, kW/kg)Batteries: Power a battery can deliver per unit mass, in watts per kilogram (W/kg). High-power cells sacrifice some energy density to deliver bursts for takeoff, acceleration or grid support.
Spectrogram (STFT, short-time Fourier transform, mel spectrogram)Maritime: An image of how a signal's frequency content changes over time, usually made with a short-time Fourier transform. It is the standard input for acoustic classifiers.
Sphalerite (zinc blende)Minerals: Zinc sulfide, the main zinc ore mineral. Indium, germanium and cadmium are recovered from it as by-products.
Spiking neural network (SNN)Computing: A neural network whose units communicate with discrete timed pulses, like biological neurons. It suits low-power neuromorphic hardware.
Spinning reserve (contingency reserve, operating reserve)Batteries: Generating or storage capacity that is online and ready to supply power within minutes if a plant or line fails.
Splash zoneMaritime: The part of an offshore structure repeatedly wetted by waves and spray, usually the most corrosive area.
Split estate (mineral estate, mineral rights, surface rights)Minerals: Land where the surface and the minerals beneath it are owned separately. The mineral estate can often be developed despite the surface owner.
Spodumene (spodumene concentrate, SC6)Batteries: A hard-rock lithium mineral mined chiefly in Australia and refined, largely in China, into lithium chemicals. It is sold as concentrate, often around 6% lithium oxide.
Sponsoring state (sponsoring State, sponsorship)Minerals: A country that backs a company's application to the International Seabed Authority and is responsible for making sure it complies.
Spot beamAerospace: A narrow antenna beam covering a small area on the ground. Many spot beams let a satellite reuse the same frequencies in different places, multiplying capacity.
SpreadFinance: The difference between the best bid and best ask price. Paid, in effect, on every round trip.
SRAM (static random-access memory, cache memory)Computing: Static random-access memory, a fast memory that holds data without refreshing but takes much more chip area per bit than DRAM. Processors use it for caches.
SSVEP (steady-state visual evoked potential)Computing: Steady-state visual evoked potential, a brain signal produced when a person looks at a light flickering at a set frequency. Brain-computer interfaces use it to detect which target a user is looking at.
Stabilization clause (stability agreement, fiscal stability agreement)Minerals: A term in a mining agreement that protects the investor from later changes in tax or law for a set period.
Stack pressureBatteries: The external pressure that holds a solid-state cell's layers in contact. Many designs need several megapascals of pressure, which adds weight and complexity at pack level.
Stage (staging)Aerospace: A self-contained section of a rocket with its own engines and propellant tanks. Dropping a stage once its propellant is spent sheds dead mass, so the remaining stages can reach higher speeds.
Staged combustion (oxidizer-rich staged combustion, oxygen-rich staged combustion, ORSC, fuel-rich staged combustion)Aerospace: A rocket engine cycle that routes the turbopump exhaust into the main combustion chamber instead of dumping it. No propellant is wasted and chamber pressure can be high, but the hot, oxygen-rich or fuel-rich gas is hard on hardware.
Stagnation temperature (total temperature)Aerospace: The temperature air reaches when brought to rest against a vehicle's surface, such as its nose or leading edges. It rises steeply with speed, reaching ≈1,000 °C at Mach 5 in the stratosphere.
Stall speedAerospace: The lowest speed at which a wing produces enough lift to hold an aircraft in level flight. Certification and ultralight rules often set limits on it.
Standard atmosphere (1976 US Standard Atmosphere, International Standard Atmosphere, US Standard Atmosphere)Aerospace: A reference model of how air temperature, pressure and density change with altitude. Engineers use it to compare aircraft performance on a common basis.
State of charge (SOC, SoC)Batteries: How full a battery is, as a percentage of its usable capacity. Battery management systems estimate it continuously; operators often avoid keeping cells near 0% or 100% to slow wear.
State of health (SOH, SoH)Batteries: A battery's present condition compared with when it was new, usually its remaining capacity as a percentage of original capacity. It decides warranty claims, resale value and second-life use.
Station-keepingAerospace: Small, regular corrections that hold a satellite or high-altitude platform at its assigned position. On geostationary satellites the propellant for station-keeping often sets working life.
Steam methane reforming (SMR)Sustainability: The dominant industrial route to hydrogen: natural gas reacts with steam at high temperature to give hydrogen and CO₂. Without capture it produces grey hydrogen.
Stibnite (Sb₂S₃, antimony trisulfide)Minerals: Antimony sulfide (Sb₂S₃), the main antimony ore mineral, found mostly in hydrothermal veins.
Stochastic defects (stochastics, stochastic failures)Computing: Random printing failures, such as missing contacts or bridged lines, caused by the small number of photons and molecules involved at EUV scales.
Stocking density (stocking rate)Maritime: The weight or number of animals per unit of water volume, which affects growth, welfare and disease risk.
Stoichiometric estimateSustainability: A calculation based on the fixed ratios in which atoms combine in a chemical reaction. It gives a physical ceiling.
Stop orderFinance: An instruction that becomes a market order once a trigger price is reached. It manages exit timing, not exit price.
Stope (stoping, stope design)Minerals: An underground opening from which ore is extracted. Stope layout and pillar sizing set how much ore can be recovered safely.
Storage tiers (nearline storage, cold storage, hot storage)Computing: Classes of storage matched to how often data is used: hot data on fast SSDs, warm or nearline data on cheaper drives, and cold data on archival media.
Store-and-forward (store and forward)Computing: Holding data locally until a connection is available, then sending it. Remote sites use it to ride out network gaps.
Stowage plan (stowage, bay plan)Maritime: The planned position of every container or cargo item aboard a ship, balancing weight, stability, port order and hazards.
Straddle carrier (automated straddle carrier)Industry: A tall vehicle that straddles a container, lifts it and carries it around a terminal. Automated versions run without drivers.
Straight-chain paraffins (n-paraffins)Sustainability: Saturated hydrocarbon molecules whose carbon atoms form a single unbranched line. Hydrotreated fats yield mostly chains of 15 to 18 carbons, which burn cleanly but turn waxy in the cold.
Stranded assetFinance: An asset that loses much of its value before the end of its expected life because of regulation, new technology or changing markets. Fossil fuel reserves that cannot be developed under tighter climate policy are a frequently cited example.
Strategic outsourcingIndustry: Deliberately buying from suppliers the activities a company does not need to control, while keeping core capabilities in-house.
Stress corrosion cracking (SCC)Industry: Cracking caused by the combined effect of tensile stress and a corrosive environment, which can fail parts well below their normal strength.
Stress testingFinance: Simulating extreme but plausible scenarios, such as a market crash or a sharp rise in interest rates, to see how a portfolio or company would hold up. It complements statistical measures that rely on normal market conditions.
Strip ratio (stripping ratio, waste-to-ore ratio)Minerals: The tonnes of waste rock that must be removed for each tonne of ore in an open-pit mine. A higher ratio means higher mining cost.
Structured equityFinance: Financing that combines ownership with debt-like protections, such as preferred shares with a liquidation preference, a guaranteed minimum return, or conversion rights. Companies use it to raise capital without issuing ordinary shares at their current price.
Sub-bottom profiler (sub-bottom profiling, SBP)Maritime: A low-frequency sonar that images sediment layers beneath the seafloor, used in cable and pipeline route surveys.
Submarine cable (undersea cable, subsea cable, submarine fiber)Computing: A fiber-optic cable laid on the seabed to carry internet traffic between continents. Repeaters along the route boost the signal; landing stations connect it to land networks.
Submarine cable components (repeater, branching unit, cable landing station, SLTE, submarine line terminal equipment, wet plant, dry plant)Computing: The main parts of an undersea cable system. Wet plant is everything in the sea, such as repeaters and branching units; dry plant is the shore equipment, including the submarine line terminal equipment (SLTE).
Submerged arc furnace (submerged-arc furnace, carbothermic reduction)Industry: An electric furnace whose electrodes are buried in the charge, used to make ferroalloys and silicon metal by carbothermic reduction, in which carbon strips oxygen from ore.
Subsea power cable (export cable, subsea export cable, interconnector)Maritime: A high-voltage cable on the seabed that carries electricity from offshore generation to shore or between grids.
Sulfide electrolyte (sulfide solid electrolyte, argyrodite, LGPS, Li₆PS₅Cl)Batteries: A solid electrolyte based on lithium sulfur compounds, such as LGPS or argyrodites. It conducts ions about as well as liquids but reacts with moisture to release toxic hydrogen sulfide, so it needs dry-room production.
Sulfuric acid (H₂SO₄, sulphuric acid)Industry: The most produced industrial chemical, used to make phosphate fertilizers, leach metals and refine fuels. Much of it is recovered from sulfur at refineries and smelters.
Sum-of-the-years' digitsFinance: An accelerated depreciation method that charges a declining fraction of cost each year, using the remaining years of life over the sum of all the years. A five-year asset takes 5/15 of its cost in year one, 4/15 in year two, and so on.
Sun-synchronous orbit (SSO)Aerospace: A near-polar low Earth orbit whose plane turns with the Sun, so the satellite passes over each place at the same local time. Earth-observation satellites favor it for consistent lighting.
Superalloy (nickel superalloy, Inconel)Industry: A nickel-, cobalt- or iron-based alloy that keeps its strength and resists oxidation at very high temperatures, used in turbines and reactors. Inconel is a common family.
Superconducting logic (single flux quantum, SFQ, RSFQ, rapid single flux quantum, ERSFQ, RQL, reciprocal quantum logic, AQFP, adiabatic quantum flux parametron)Computing: Digital circuits built from superconductors and Josephson junctions that switch with very little energy. Families include RSFQ, energy-efficient ERSFQ, RQL and the adiabatic AQFP.
Superconducting qubit (transmon, transmons, superconducting quantum computer)Computing: A qubit made from a superconducting circuit cooled to millikelvin temperatures. Transmons, the most common type, use Josephson junctions; gates are fast but coherence is short.
Supercritical CO₂ power cycle (sCO₂, sCO2, supercritical CO2, supercritical carbon dioxide, sCO₂ Brayton cycle)Industry: A closed Brayton power cycle that uses CO₂ above its critical point, 31 °C and ≈7.4 MPa, as the working fluid. Its dense fluid allows small turbines and high efficiency at moderate temperatures.
SuperpositionComputing: A quantum state that combines several possible values at once, with each outcome appearing with some probability when measured.
Superstructure (deckhouse, accommodation block)Maritime: The structures built above a ship's main deck, such as the deckhouse and bridge, holding accommodation, controls and machinery.
Supplier qualification (supplier approval)Industry: The testing and approval a buyer requires before a supplier's part or process can be used in production. In aerospace and defense it can take many months, which slows switching suppliers.
Surface codeComputing: The leading quantum error-correcting code, which arranges qubits in a grid and needs only neighboring connections. It needs many physical qubits per logical qubit.
Surge capacity (surge production)Industry: The ability to raise output quickly in an emergency or war, which needs spare equipment, workforce and inventories.
Survivorship biasFinance: Testing on a universe that excludes companies that were later delisted or removed, which flatters results because failures are absent.
Sustainable aviation fuel (SAF)Sustainability: Jet fuel made from non-fossil sources, such as HEFA from fats and oils. Because it draws on the same lipid feedstocks as HVO, the two compete directly for limited residues.
SWAP overhead (SWAP gate)Computing: Extra operations needed to move quantum information between qubits that are not directly connected. Limited connectivity raises it and adds errors.
SWaP-C (SWaP, size, weight, power and cost)Aerospace: Size, weight, power and cost: the four constraints that decide whether a sensor, computer or radio fits on a platform. Small drones and satellites are especially limited by them.
Swarf (magnet swarf)Minerals: Fine metal chips and sludge from cutting and grinding. In magnet making it is a major feed for recycling.
SwashplateAerospace: The mechanical linkage that changes the pitch of helicopter rotor blades as they turn, letting the pilot tilt and adjust the rotor's thrust.
Syntactic foamMaritime: A buoyant composite of hollow glass microspheres in resin that resists crushing at depth, used for flotation on deep vehicles.
System boundarySustainability: The line that defines which processes a lifecycle assessment includes and which it leaves out. Moving the boundary changes the result.
System expansion (substitution method)Sustainability: Avoiding allocation by giving the main product a credit for the product its co-product displaces elsewhere. Soybean meal, for example, earns a credit for the feed protein it replaces. The result depends heavily on which product is assumed to be displaced and can even turn negative.
System-on-chip (SoC)Computing: A single chip that combines processors, memory controllers, graphics, AI blocks and input-output functions. Phones, drones and embedded devices run on them.

T

Tabular numeralsFinance: Digits of equal width so that figures align in columns. Used for all financial data on THR.
Tail-risk diversifiersFinance: Holdings expected to hold their value or rise during severe market declines, which can offset losses elsewhere in a portfolio. Examples discussed in research include long volatility positions, trend-following strategies and high-quality government bonds.
Tailings (tailings dam, tailings storage facility, TSF)Minerals: The finely ground waste left after minerals are extracted, usually stored behind dams or as dry stacks. Old tailings can sometimes be reprocessed for metal.
Tallow (animal fat)Sustainability: Rendered fat from cattle, sheep or other livestock. Its HVO carries a RED typical value of 16.0 g CO₂e/MJ, but its consequential footprint depends on the category and on what replaces it.
Tantalum (Ta₂O₅, tantalum pentoxide)Minerals: A rare, corrosion-resistant refractory metal. Its main use is capacitors; it is also used in superalloys, chip wiring barriers and medical implants. Ore is priced on Ta₂O₅ content.
Tantalum capacitor (tantalum capacitors, tantalum-polymer capacitor)Minerals: A small capacitor that uses tantalum powder and a thin tantalum oxide layer to store a lot of charge in little space, valued in phones, cars and defense electronics.
Tapered integration (partial integration, quasi-integration)Industry: Making part of an input in-house while still buying the rest from outside suppliers, to keep both control and market discipline.
Tariff-rate quota (TRQ)Industry: A trade limit that charges a low tariff up to a set import volume and a higher tariff beyond it.
Tax deferralFinance: Postponing tax to a later period, for example through retirement accounts, accelerated depreciation, or holding assets whose gains are taxed only when sold. Deferral usually changes when tax is paid rather than whether it is paid.
Tax timing strategiesFinance: Choosing when income, gains, losses and deductions are recognised in order to manage the tax owed in a given year. Examples include accelerating deductions, deferring income and realizing losses to offset gains.
Technical Standard Order (TSO)Aerospace: An FAA minimum performance standard for specific parts and equipment, such as batteries or avionics. Meeting one lets a part be approved once and installed in many aircraft.
Technology readiness level (TRL)Aerospace: A 1–9 scale, developed at NASA, for how mature a technology is, from basic principles observed to proven in operation. Agencies and investors use it to judge development risk. See the table
Telemetry, tracking and command (TT&C, telemetry, tracking and control)Aerospace: The radio links and ground systems used to monitor a spacecraft's health, measure its position and send it commands.
Teleoperation (remote operation, remote-controlled cranes)Industry: Operating a vehicle or crane remotely from a control room, often as a step toward full autonomy.
Temporary full expensing / instant asset write-offFinance: Australian tax measures that let businesses deduct the full cost of eligible assets in the year they are first used instead of depreciating them. Temporary full expensing applied from 2020 to 2023; the instant asset write-off is a recurring measure with a cost threshold for smaller businesses.
Terminal operating system (TOS)Industry: Software that plans and controls a container terminal: ship stowage, yard positions, equipment dispatch and gate traffic.
Terminal tractor (yard truck, yard tractor, port tractor, terminal truck)Industry: A short truck that tows container chassis between quay, yard and gates. It is a leading target for battery power and autonomy.
TEU (twenty-foot equivalent unit, FEU)Industry: Twenty-foot equivalent unit, the standard measure of container volume. A 40-foot container counts as 2 TEU; ship and port capacity are quoted in TEU.
Texas SB 6 (Senate Bill 6)Computing: A 2025 Texas law setting rules for loads of 75 MW or more, such as data centers and crypto miners. It requires remote curtailment equipment, interconnection study fees and approval of co-location deals.
The Area (international seabed area, areas beyond national jurisdiction)Minerals: Under the Law of the Sea, the seabed beyond any country's national jurisdiction, whose minerals are managed by the International Seabed Authority.
Thermal design power (TDP)Computing: The maximum sustained heat a chip is designed to produce, in watts, which its cooling must remove.
Thermal energy storage (TES, heat storage, heat battery)Batteries: Storing energy as heat or cold in materials such as sand, brick, molten salt or water, for later use as heat or electricity. It is far cheaper than batteries for delivering heat.
Thermal management (battery thermal management, BTMS)Batteries: Keeping battery cells in their best temperature range, typically ≈15–35 °C, with air, liquid or immersion cooling and heating. It affects life, safety, power and charging speed.
Thermal propagation (propagation, cell-to-cell propagation)Batteries: The spread of thermal runaway from one cell to its neighbors. Pack designs use spacing, barriers and cooling to stop one failed cell from igniting the whole pack.
Thermal protection system (TPS, heat shield)Aerospace: The materials that shield a vehicle from heating during reentry or hypersonic flight, such as tiles, blankets and heat shields. Ablative types char and erode to carry heat away; reusable types must survive many flights.
Thermal runawayBatteries: A self-heating chain reaction in which a failing cell releases heat faster than it can shed it, often ending in venting, fire or explosion. Causes include internal shorts, overcharging, damage and overheating.
Thermo-optic and electro-optic effects (thermo-optic effect, electro-optic effect)Computing: Ways to tune optical devices. The thermo-optic effect changes refractive index with heat; the electro-optic effect changes it with an electric field, which is much faster.
Thermophotovoltaics (TPV, thermophotovoltaic)Batteries: Turning heat directly into electricity with photovoltaic cells tuned to the infrared light that glowing hot materials emit. It could let very hot heat stores return power without turbines.
Thin-film lithium niobate (TFLN, lithium niobate on insulator, LNOI)Computing: A thin layer of lithium niobate crystal bonded on insulator, used for very fast, low-power optical modulators.
ThriftingIndustry: Cutting the amount of precious metal used per product, such as per catalytic converter, through better design.
Throttling (deep throttling, throttle range)Aerospace: Varying an engine's thrust during flight. Deep throttling, to a small fraction of full thrust, is needed for propulsive landing and for gentle lunar descent.
Thrust gapAerospace: A speed range in which neither engine of a combined-cycle system gives enough thrust: the turbine is running out of performance and the ramjet is not yet efficient.
Thrust vectoring (vectored thrust)Aerospace: Steering by changing the direction of engine or rotor thrust, instead of relying only on control surfaces. Tiltrotors, many eVTOLs, some fighters and most rockets use it.
Tier 1 exposureSustainability: THR's shorthand for a Tier 2 pathway that would fall into Tier 1 under a different, credible set of assumptions, most often GLOBIOM-type ILUC values or consequential accounting.
Tier 1, Tier 2, Tier 3 and Tier 4Sustainability: THR's four-step classification that separates "lower than fossil diesel" from "carbon-neutral", defined against the 94 g CO₂e/MJ fossil comparator. It is a THR framework, not a regulatory category. See the table
Tiltrotor (proprotor, prop-rotor, tilt rotor)Aerospace: An aircraft with rotors at its wingtips that tilt upward to hover like a helicopter and forward to cruise like an airplane. It is faster than a helicopter but mechanically complex.
Time difference of arrival (TDOA)Maritime: Locating a receiver or transmitter from differences in signal arrival times between stations or sensors.
Tip speed (tip Mach number, rotor tip speed)Aerospace: The speed of a rotor or propeller blade's tip. Higher tip speeds give more thrust but more noise, and near the speed of sound shock waves form, so quiet designs run slower tips.
Tipping fee (gate fee)Batteries: A fee a recycler or disposal site charges to accept waste. Recyclers charge tipping fees for low-value batteries such as LFP, whose metals do not cover processing costs.
Tokamak (ITER, high-temperature superconducting tokamak)Industry: A doughnut-shaped fusion device that holds plasma in place with strong magnetic fields. It is the most studied fusion design; ITER in France is the largest under construction.
Token (tokens)Computing: The unit of text a language model reads and writes, typically a word or part of a word. Model usage and pricing are counted in tokens.
Toll processing (toll treatment, toll refining, tolling)Minerals: Processing another company's ore or concentrate for a fee, without taking ownership of the metal.
Tonne-kilometre (tkm)Sustainability: Moving one tonne of freight one kilometre. Freight emissions per tkm let fleets compare fuels on the work actually done.
Toolpath (post-processor, G-code)Industry: The programmed route a cutting tool follows to make a part. CAM software generates it, and a post-processor translates it into code for a specific machine.
Touchdown and lift-off area (TLOF, touchdown and liftoff area)Aerospace: The load-bearing central pad at a heliport or vertiport where an aircraft touches down and lifts off. In FAA vertiport guidance it is at least one rotor diameter across.
Towed array (towed array sonar, towed line array)Maritime: A long line of hydrophones towed far behind a ship or submarine, away from its own noise, to detect quiet low-frequency sounds.
Tower catch (booster catch, chopstick arms, chopsticks)Aerospace: A recovery method in which arms on the launch tower grab a returning booster in mid-air instead of letting it land on legs. Dropping the landing legs saves mass and can speed turnaround, but a failed catch puts the tower at risk.
TPU (tensor processing unit)Computing: Tensor processing unit, Google's custom AI accelerator for training and inference, offered mainly through Google Cloud.
TraceabilitySustainability: The ability to follow a feedstock back to its verified origin through every transaction. It is the main defense against fraudulent or mislabeled waste feedstock.
Training (model training, pre-training)Computing: The compute-heavy process of adjusting a model's weights on data until it performs a task well. Training a frontier model can occupy tens of thousands of GPUs for months.
Trans-lunar injection (TLI)Aerospace: The engine burn that sends a spacecraft from Earth orbit onto a path to the Moon. Payload to it measures a rocket's usefulness for lunar missions.
TransesterificationSustainability: The reaction that makes FAME: fats react with methanol to form methyl esters and glycerol. It uses less energy than hydroprocessing for clean oils, which can make biodiesel lower-emission than HVO for oilseed feedstocks.
Transformer (transformer model, attention mechanism)Computing: The neural network design behind most large language models, built around an attention mechanism that relates every token to every other. Its compute cost grows with the square of input length.
TransitionAerospace: The flight phase in which a VTOL aircraft shifts between rotor-borne hover and wing-borne cruise. Lift, control and power needs change rapidly, which makes it a focus of testing.
Transport & Environment (T&E)Sustainability: A Brussels-based advocacy group campaigning for cleaner transport, and a frequent critic of crop-based and imported waste-based biofuels.
Traveling-wave tube (TWT)Aerospace: A vacuum tube that amplifies microwave signals by passing them alongside an electron beam. Satellites and radars use them in high-power transmitters, with permanent magnets focusing the beam.
Treatment and refining charges (TC/RC, TC/RCs, treatment charge, refining charge, payability, payable metal)Minerals: Fees a smelter deducts for processing concentrate, set per tonne and per unit of payable metal. They rise when concentrate is plentiful and fall when it is scarce.
TriglycerideSustainability: The main molecule in fats and oils: three fatty-acid chains attached to a glycerol backbone.
Trim into strengthFinance: A market phrase for selling part of a position while its price is rising, rather than after it falls. It reduces the size of a position and realises some of the gain while keeping the rest.
Tritium breeding (tritium fuel cycle, breeding blanket)Industry: Producing tritium fuel inside a fusion plant by hitting lithium with neutrons from the reaction. Plants must breed their own because tritium is scarce.
Troy ounce (oz t, troy oz)Industry: The unit for precious metals, equal to ≈31.1 g, slightly heavier than an ordinary ounce.
True and calibrated airspeed (true airspeed, calibrated airspeed)Aerospace: Calibrated airspeed is the instrument reading corrected for installation errors; it governs how the aircraft handles. True airspeed is the actual speed through the air, which exceeds calibrated airspeed at altitude.
Tunable coupler (tunable couplers)Computing: A circuit element between qubits whose coupling can be switched on and off, reducing unwanted interactions in superconducting processors.
Tungsten (wolfram)Minerals: A very dense, hard metal with the highest melting point of any metal, ≈3,422 °C. Most goes into cemented carbide tools; defense uses include armor-piercing rounds.
Tungsten heavy alloy (heavy alloy, WHA)Minerals: A dense alloy of ≈90–97% tungsten with nickel and iron or copper, used for counterweights, radiation shielding and kinetic penetrators.
Tungsten ore minerals (scheelite, wolframite)Minerals: Scheelite (calcium tungstate) and wolframite (iron-manganese tungstate), the two minerals from which almost all tungsten is mined.
Tungsten trioxide basis (WO₃, WO3, tungsten trioxide)Minerals: Tungsten ore grades and concentrate prices are quoted in tungsten trioxide (WO₃) content, not metal. WO₃ is ≈79% tungsten by weight.
Turbine-based combined cycle (TBCC)Aerospace: A propulsion system that pairs a turbine engine for takeoff and low speeds with a ramjet or scramjet for high speeds. It could enable reusable, runway-launched hypersonic aircraft, but handing off between the two engines remains a major engineering challenge.
Turboexpander (turbo-expander)Industry: A turbine through which high-pressure gas expands to drive a generator or compressor, used in power cycles and gas processing.
TurbofanAerospace: A jet engine in which a large fan pushes some air around the engine core, called bypass air. It is quieter and more fuel efficient than a turbojet at subsonic speeds.
TurbojetAerospace: A jet engine that passes all of its intake air through the compressor, combustor and turbine. It is simple and suits small, fast, short-lived vehicles such as aerial targets and cruise missiles.
TurboshaftAerospace: A gas-turbine engine that delivers power through a rotating shaft instead of jet thrust. It drives the rotors of helicopters and tiltrotors.
TV white spaceComputing: Unused television broadcast frequencies that can carry long-range wireless broadband in rural areas.
Two-year rule (two year rule)Minerals: An UNCLOS provision letting a sponsoring state require the ISA to finish exploitation rules within two years. Nauru triggered it in 2021; the deadline passed in 2023 without rules.
Type certificate (type certification)Aerospace: A regulator's approval that an aircraft, engine or propeller design meets its airworthiness standards. It is the main hurdle for a new design; building and flying it commercially need further approvals.
Type Inspection Authorization (TIA)Aerospace: FAA approval to begin official certification flight tests with FAA pilots, issued once a design is mature and its compliance data are largely complete. It marks the final phase of type certification.
Type ratingAerospace: A pilot qualification for a specific aircraft type, required for large, jet-powered or otherwise complex aircraft, including powered-lift.

U

UAS groups 1–5 (DoD UAS groups)Aerospace: The US military's five size classes for uncrewed aircraft, set by weight, normal operating altitude and speed. See the table
UL 1973Batteries: A UL safety standard for batteries used in stationary storage, light electric rail and similar applications. It covers the battery system itself, not the full installation.
UL 9540Batteries: The UL safety standard for complete energy storage systems, including batteries, inverters and controls. US building and fire codes commonly require listing to it.
UL 9540ABatteries: A UL test method that measures how fire spreads from a cell in thermal runaway to modules, units and the installation. Its results set spacing and fire protection under NFPA 855.
Ultra-large container vessel (ULCV, ULCS, ultra-large container ship, megaship)Maritime: The largest class of container ship, roughly 400 m long and able to carry ≈20,000–24,000 TEU. Only deep, well-equipped hub ports can handle them.
Ultra-low-sulfur diesel (ULSD)Sustainability: Fossil diesel with sulfur content below 15 parts per million (U.S.) or 10 ppm (EU), the standard road diesel today.
Ultra-supercritical steam (USC, A-USC, advanced ultra-supercritical)Industry: Steam power plants running above the critical point of water at very high temperature and pressure, giving higher efficiency than older subcritical plants.
UN 38.3 (UN38.3)Batteries: The UN test series that lithium cells and batteries must pass before being shipped, covering altitude, temperature, vibration, shock, short circuit and overcharge. It sits in the UN Manual of Tests and Criteria.
UN 3480 and UN 3481 (UN3480, UN3481, UN 3480, UN 3481, Class 9 dangerous goods)Batteries: The UN shipping numbers for lithium-ion batteries shipped alone (UN 3480) and packed with or in equipment (UN 3481). They fall in Class 9 dangerous goods. For air transport, many shipments must be at no more than 30% state of charge.
UNCLOS (United Nations Convention on the Law of the Sea, Law of the Sea, Part XI, 1994 Implementation Agreement)Minerals: The 1982 UN Convention on the Law of the Sea. Its Part XI, as changed by a 1994 agreement, governs mining in the Area. The US has not ratified it.
Uncrewed aerial vehicle (UAV, unmanned aerial vehicle, drone)Aerospace: An aircraft flown with no pilot on board, either remotely or autonomously. Sizes range from palm-sized quadcopters to airliner-sized surveillance aircraft.
Uncrewed aircraft system (UAS, unmanned aircraft system, sUAS, small unmanned aircraft system)Aerospace: An uncrewed aircraft together with everything needed to operate it: the ground control station, data links and support equipment. Regulators and militaries use the term because the aircraft alone is not the whole system.
Uncrewed undersea vehicle (UUV, UUVs, unmanned undersea vehicle, unmanned underwater vehicle)Maritime: Any underwater vehicle without people aboard, either remotely controlled through a tether or operating autonomously.
Underground mining (underground mine, deep-level mining)Minerals: Mining through shafts, declines and tunnels to reach deeper or narrower ore bodies. It costs more per tonne than open-pit mining but disturbs less surface.
Underwater acoustic communication (acoustic modem, acoustic link, underwater acoustic modem)Maritime: Sending data through water by sound, the only practical long-range underwater channel, at low data rates because of limited bandwidth and multipath.
Underwater acoustic datasets (ShipsEar, DeepShip)Maritime: Public recordings used to train and benchmark ship-noise classifiers, such as ShipsEar from the Spanish coast and DeepShip, with ≈47 hours from 265 ships.
Underwater acoustic target recognition (UATR, acoustic target classification)Maritime: Classifying ships, submarines and marine life from the sounds they radiate, increasingly with machine learning on spectrograms.
Underwater optical communication (blue-green laser communication, optical modem)Maritime: Short-range, high-rate data links through water using blue-green light, which seawater absorbs less than other wavelengths.
Underwater radiated noise (URN, ship noise, underwater noise)Maritime: Sound that ships emit into the sea, mostly from propeller cavitation and machinery, which can disturb marine life. The IMO's guidelines to reduce it, revised in 2023, are voluntary.
Underway replenishment (replenishment at sea, UNREP)Maritime: Transferring fuel, stores or munitions between ships while both are moving, which lets a fleet stay at sea for long periods.
UnicornFinance: A privately held startup valued at $1 billion or more. The valuation usually comes from the price paid in its latest funding round rather than from trading on a public market.
Union Database for Biofuels (UDB)Sustainability: The European Commission's central database, rolled out from 2024, that records biofuel and feedstock transactions from origin to market so that the same batch cannot be claimed twice or relabeled.
Units of productionFinance: Depreciation based on how much an asset is used, such as tonnes mined or hours operated, relative to its expected total output. It matches the expense to activity and is common in mining and energy.
UniverseFinance: The full set of securities a strategy may hold, defined by rules such as listing venue, liquidity, and price. THR also uses it for the set of companies the desk tracks.
Unpatented mining claimFinance: A claim on US federal land that gives the holder the right to explore for and extract certain minerals without owning the land itself. It must be kept in good standing with annual maintenance fees to the Bureau of Land Management.
Unrealized gainFinance: An increase in the value of an investment that is still held. It exists only on paper and can shrink or disappear as the price moves.
Unreliable Entity ListMinerals: China's list of foreign companies it deems harmful to its interests, which can be barred from trading with or investing in China.
Unstart (inlet unstart)Aerospace: A sudden breakdown of supersonic flow in an engine inlet, in which the shock wave is pushed out of the inlet and thrust collapses. It can cause violent yawing and was a known hazard on Mach 3 aircraft.
Upmass and downmass (upmass, downmass)Aerospace: Upmass is the mass carried from the ground to orbit; downmass is the mass returned safely to Earth. Downmass capacity is much scarcer, which matters for returning experiments and products made in orbit.
Upper stage (second stage)Aerospace: A rocket stage that ignites after the first stage separates and carries the payload the rest of the way to orbit. It often needs an engine that can restart in space to reach high or multiple orbits. Most upper stages are still discarded after one flight.
Uptime Institute tiers (Tier III, Tier IV, Tier III data center)Computing: A widely used rating of data center reliability, from Tier I, with basic capacity and no redundancy, to Tier IV, which is fault tolerant. Tier III sites can be maintained without shutting down.
Urban air mobility (UAM)Aerospace: The part of advanced air mobility focused on short passenger and cargo flights within cities, such as air taxis between vertiports.
Urban miningBatteries: Recovering metals from discarded products such as batteries and electronics instead of mining ore.
Urea (CO(NH₂)₂)Industry: The world's most used nitrogen fertilizer, made from ammonia and CO₂, containing 46% nitrogen. It is also used in diesel exhaust treatment.
US Commercial Space Launch Competitiveness Act (CSLCA, SPACE Act of 2015, 51 U.S.C. 51303)Minerals: A 2015 US law that lets US citizens own and sell resources they extract from asteroids and other celestial bodies (51 U.S.C. §51303).
US Munitions List (USML, United States Munitions List)Aerospace: The list of defense articles and services controlled under ITAR, organized in 21 categories, such as Category IV for launch vehicles and missiles and Category XI for military electronics.
USDA feedstock carbon-intensity frameworkSustainability: The U.S. Department of Agriculture's framework for quantifying farm-level feedstock emissions, including practices that build soil carbon, so they can lower a fuel's 45Z carbon intensity. It took effect on 29 July 2026.
Used cooking oil (UCO)Sustainability: Oil and fat already used for frying, collected from restaurants and food processors. It is the lowest-carbon mainstream HVO feedstock on attributional accounting, at about 14 g CO₂e/MJ, but supply is limited and prone to mislabeling.
Useful loadAerospace: The weight an aircraft can carry beyond its empty weight: crew, passengers, cargo and usable fuel.
USGS critical minerals list (List of Critical Minerals, critical minerals list, US critical minerals list)Minerals: The US list of minerals judged essential and at supply risk, required by the Energy Act of 2020. The final 2025 list, released in November 2025, has 60 entries, adding copper, silver and uranium.
USGS Mineral Commodity Summaries (Mineral Commodity Summaries, USGS MCS, Minerals Yearbook)Minerals: The US Geological Survey's annual report on production, reserves, prices, trade and import reliance for ≈90 minerals, published early each year.
USMCA (United States-Mexico-Canada Agreement)Industry: The United States-Mexico-Canada Agreement, the North American free trade deal that replaced NAFTA in 2020. Goods that meet its origin rules trade with lower duties.
UUV size classes (XLUUV, extra-large UUV, XL-AUV, LDUUV, large-displacement UUV, heavyweight UUV)Maritime: US Navy classes of uncrewed undersea vehicles by diameter and weight: man-portable, lightweight, heavyweight, large-displacement and extra-large. Extra-large vehicles, over ≈10 m, launch from piers rather than submarines.

V

Vacuum-optimized engine (vacuum engine)Aerospace: An engine with a large nozzle designed for the near-vacuum of space, where it gives more thrust and efficiency. The same nozzle would perform poorly at sea level, so first stages use shorter sea-level nozzles.
ValuationFinance: An estimate of what a company or asset is worth, based on what it owns today and the cash it is expected to generate in future. Common methods are discounted cash flow, comparisons with similar companies, and the value of net assets.
Value at risk (VaR)Finance: An estimate of the loss a portfolio should not exceed over a set period at a given confidence level. A one-day 95% VaR of $1 million means losses larger than $1 million are expected on about 5% of days; it says nothing about how large those losses can be.
Value stackingBatteries: Earning several revenue streams from one storage asset, such as arbitrage, reserves and backup power, to make it pay.
Variational quantum algorithms (VQE, variational quantum eigensolver, QAOA, quantum approximate optimization algorithm)Computing: Hybrid algorithms in which a quantum computer evaluates a parameterized circuit and a classical computer adjusts the parameters. VQE targets chemistry problems; QAOA targets optimization.
Vector database (vector store, vector search)Computing: A database built to store embeddings and find the ones most similar to a query quickly, even across billions of entries.
Vegetable-oil substitutionSustainability: The tendency of vegetable oils to replace one another in global markets because they are largely interchangeable. Extra demand for any one oil is ultimately met, at the margin, by the cheapest, which is usually palm.
Vertical integration (vertically integrated)Industry: Owning more steps of a supply chain inside one company, instead of buying from suppliers. It gives control and learning but ties up capital and can reduce flexibility.
VertiportAerospace: A site where VTOL aircraft such as eVTOLs take off, land, charge and board passengers, on the ground, on rooftops or at airports. In the US, FAA Engineering Brief 105A gives voluntary design guidance.
Virgin vegetable oilSustainability: Oil from fresh crops that has not been used. Its price is a benchmark for waste oils.
Virtual unwrappingComputing: Digitally flattening the layers of a rolled or folded object, such as a carbonized scroll, from a 3D scan so its surface can be read without opening it.
Volatiles (lunar volatiles, volatile resources)Minerals: Substances that vaporize easily, such as water, carbon dioxide, ammonia and hydrogen, which may be trapped in lunar polar soil or asteroids.
Volatilization roasting (roasting)Industry: Heating a sulfide concentrate in air so the target metal leaves as an oxide vapor that is collected as fume. It is used to make crude antimony trioxide.
Voltaic pileBatteries: The first practical chemical battery, built by Alessandro Volta in 1800 from stacked zinc and copper discs separated by cloth soaked in salt water. It gave a steady current, which made early electrochemistry possible.
Volumetric energy densitySustainability: Energy per litre of fuel. HVO holds about 34 MJ per litre against about 36 for fossil diesel, so slightly more litres are needed for the same work.
VTOL (vertical takeoff and landing)Aerospace: Able to take off and land vertically, without a runway. The term covers helicopters, tiltrotors, eVTOLs, some jets and many drones.

W

Wafer (silicon wafer, 300 mm wafer)Computing: A thin disc of pure silicon, usually 300 mm across, on which many chips are built at once before being cut apart.
Wafers per hour (wph)Computing: Lithography tool throughput, the number of wafers exposed per hour. It drives cost per layer as much as tool price does.
WashcoatIndustry: The porous coating on a catalyst's ceramic honeycomb that holds the precious metal particles and gives them a large surface area.
Wassenaar Arrangement (Wassenaar)Aerospace: A multilateral export-control regime in which participating states agree on lists of conventional arms and dual-use goods to control, then apply them in national rules.
Waste oil (waste-oil HVO)Sustainability: HVO made from wastes and residues such as used cooking oil and animal fats rather than crop oils. Waste status is attested by certification bodies and earns lower default emissions and extra policy support.
Waste statusSustainability: The official recognition that a material is a waste or residue rather than a product, which unlocks favorable accounting and incentives. Because the label is valuable, it is a target for fraud.
Watt-hour (Wh, kWh, MWh, GWh, kilowatt-hour, megawatt-hour, gigawatt-hour)Batteries: A unit of energy equal to one watt for one hour, or 3,600 joules. Batteries are sized in watt-hours, kilowatt-hours (kWh), megawatt-hours (MWh) and gigawatt-hours (GWh).
Wave energy converter (WEC, wave energy device, wave converter, wave power)Maritime: A device that turns the motion of ocean waves into electricity, such as point absorbers, attenuators and oscillating water columns.
Waveguide (optical waveguide)Computing: A structure that confines and guides light along a path on a chip or in a fiber, like a wire for light.
Wavelength-division multiplexing (WDM, dense wavelength-division multiplexing, DWDM)Computing: Sending several data streams on different wavelengths of light down one waveguide or fiber at once.
WaveriderAerospace: A hypersonic vehicle shape designed to ride on its own shock wave, using the high-pressure air beneath it for lift. It improves the lift-to-drag ratio at hypersonic speeds.
Wear leveling (wear-leveling)Computing: Spreading writes evenly across a flash drive's cells so no area wears out early.
Weather window (sea-state window, operational window)Maritime: A period of sea and weather conditions calm enough for a marine operation, such as cable repair, installation or diving.
WEF Global Lighthouse Network (Lighthouse factory, Global Lighthouse Network)Industry: A World Economic Forum program that names factories judged to lead in applying digital and automation technology at scale.
Well-to-tank, tank-to-wheel and well-to-wheelSustainability: Fuel lifecycle stages. Well-to-tank covers production and delivery to the vehicle; tank-to-wheel covers combustion in the engine; well-to-wheel is both together.
Wet-process phosphoric acid (phosphoric acid, wet process, acidulation)Industry: Phosphoric acid made by dissolving phosphate rock in sulfuric acid. It is the base for phosphate fertilizers and leaves large volumes of phosphogypsum.
Windage (windage loss)Batteries: Drag on a fast-spinning rotor from the surrounding air. Flywheels spin in a vacuum to reduce it.
WinsoriseFinance: To cap extreme values at a stated percentile before further calculation, limiting the influence of outliers.
World Radiocommunication Conference (WRC)Aerospace: The ITU treaty conference, held every three to four years, that revises the international Radio Regulations, including spectrum for satellites and new services such as high-altitude platforms.
Write endurance (program/erase cycles, write/erase cycles)Computing: How many times flash memory can be written and erased before it wears out, often given as program/erase cycles or drive writes per day.
WTO DS431 (DS431, China – Rare Earths)Minerals: The World Trade Organization case in which China's export duties and quotas on rare earths, tungsten and molybdenum were ruled inconsistent with its trade commitments in 2014.

Y

Yard cranes (rubber-tyred gantry crane, RTG, rail-mounted gantry crane, RMG, automated stacking crane, ASC)Industry: Gantry cranes that stack and retrieve containers in a terminal's storage yard. Rubber-tyred versions move freely; rail-mounted and automated stacking cranes run on fixed tracks.
Yield-price elasticitySustainability: How strongly crop yields respond to higher prices, through more fertilizer or better management rather than more land. A higher elasticity means less land clearing and lower ILUC. CARB calls it the most influential GTAP-BIO parameter, tested across 0.05 to 0.35.

Z

Z-scoreFinance: A value expressed as the number of standard deviations from the mean of its group. Used to make different variables comparable.
Zeolite (zeolites, molecular sieve)Industry: A crystalline aluminosilicate mineral with a regular network of tiny pores, used as a catalyst, ion exchanger, adsorbent and molecular sieve.
Zero-trust architecture (zero trust, zero-trust)Computing: A security approach in which no user or device is trusted by default, even inside the network, and every access is verified.
Zero-volt storage (zero-volt transport)Batteries: The ability of a cell to be fully discharged to 0 V for storage or shipping without damage. Sodium-ion cells can do this because they use aluminum current collectors, which do not corrode at 0 V.