Glossary

Web3 words, in plain English

Every definition links to its source. More words arrive with each module.

Account abstraction: Letting each account set its own rules for checking transactions, written as smart contract code. Source: Ethereum Improvement Proposals (V. Buterin, Y. Weiss, D. Tirosh and others). From Multisig and smart accounts.
ACH: A US network through which banks send each other batches of electronic payments, such as payroll. Source: Board of Governors of the Federal Reserve System, read 22 October 2026. From Banking and crypto.
Actively Validated Service (AVS): A service, such as a price oracle or a bridge, that is secured by restaked ETH and pays rewards for it. Source: ethereum.org (read 24 October 2026; page last updated 15 May 2026). From Staking and yield.
Address: The identifier you share so others can pay you. On Ethereum, it is the last 20 bytes of the Keccak-256 hash of the public key, written as 0x and 40 hex characters. Source: ethereum.org (developer documentation). From Wallets, keys and seed phrases.
Address poisoning: Planting a look-alike address in someone's transaction history so that they copy it and send funds to the attacker. Source: Etherscan Information Center (a block explorer's help pages), Taro Tsuchiya, Jin-Dong Dong, Kyle Soska and Nicolas Christin (Carnegie Mellon University and independent), Proceedings of the 34th USENIX Security Symposium. From Security and common attacks.
Aggregation: Combining many reports into one value, often by taking the median. Source: Chainlink documentation, Pyth Network documentation. From Oracles.
Airdrop: Tokens sent to many addresses at once, for example as part of a marketing campaign or after a hard fork. Source: US Internal Revenue Service (IRS), HM Revenue & Customs (HMRC), Cryptoassets Manual. From Crypto tax basics.
Algorithmic stablecoin: A stablecoin that holds few or no reserve assets and tries to keep its peg with rules that change its supply. Source: Board of Governors of the Federal Reserve System (Garth Baughman, Francesca Carapella, Jacob Gerszten and David Mills). From Stablecoins.
Allowable costs: In the UK, the costs you may take off a gain, such as the price paid and transaction fees. Source: HM Revenue & Customs (HMRC), Cryptoassets Manual. From Crypto tax basics.
Allowance: How many of your tokens an approved spender is still allowed to withdraw. Source: Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin). From Security and common attacks.
Allowance: The amount another address may still spend from your ERC-20 tokens. You set it with approve, and calling approve again replaces it. Source: Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin). From Token standards.
Allowlist: The list of approved wallets that a permissioned token can move to. Many documents call it a whitelist. Source: Ethereum Improvement Proposals (Lebrun, Malghem, Thizy, Falempin and Boudjemaa), status Final, Franklin Templeton Trust, filed with the US Securities and Exchange Commission. From Real-world assets.
Amount realized: In the US, what you receive when you sell, less the fees you paid to make the sale. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Annual Exempt Amount: The UK's tax-free allowance for capital gains each tax year. It was £3,000 as of October 2026. Source: GOV.UK. From Crypto tax basics.
APR (annual percentage rate): A yearly rate that does not include the effect of compounding. Source: Electronic Code of Federal Regulations, US Government (read 24 October 2026, through the eCFR's own content service). From Staking and yield.
APY (annual percentage yield): A yearly rate that includes the effect of compounding, worked out over a 365-day year. Source: Electronic Code of Federal Regulations, US Government (read 24 October 2026, through the eCFR's own content service), Investor.gov, US Securities and Exchange Commission (read 24 October 2026). From Staking and yield.
Ask: The lowest price a seller will accept right now. Source: Investor.gov, US Securities and Exchange Commission. From Market makers: loan or retainer?.
Asset-referenced token (ART): Under EU law, a crypto-asset that aims to keep a stable value by referencing another value, right or mix of them, and is not an e-money token. Source: European Parliament and Council of the European Union, Official Journal of the European Union (EUR-Lex). From Stablecoins.
ASU 2023-08 (ASC 350-60): The FASB's 2023 rule that requires crypto assets in its scope to be measured at fair value, with changes recognised in net income each reporting period. Source: Financial Accounting Standards Board (FASB). Read from the FASB's own file store, because fasb.org refused our automated download. From Crypto accounting basics.
Attestation: An accountant's check of one claim, such as 'reserves are at least equal to the tokens', at a set date. Source: Circle Internet Group, with an examination report by its independent accountants, BDO Advisory Services and Tether International. From Stablecoins.
Audit: An independent check of a company's full financial statements for a period, such as a year. Source: Public Company Accounting Oversight Board (read via the Internet Archive copy of 16 December 2024, because pcaobus.org refused our automated download), Tether press release. From Stablecoins.
Automated market maker (AMM): A smart contract that holds a pool of two tokens and prices trades with a formula instead of matching buyers and sellers. Source: Uniswap Developers documentation (read 22 October 2026), Hayden Adams, Noah Zinsmeister, Moody Salem, River Keefer and Dan Robinson. From Exchanges, DEXs and AMMs.
Average cost: A cost method that spreads the cost of all the units held evenly across them. IFRS calls it the weighted average cost formula. Source: IFRS Foundation (read 24 October 2026), Deloitte (DART). From Crypto accounting basics.
Average fill price: What an order paid or received in total, divided by the number of tokens, when it fills at several prices. Source: Investor.gov, US Securities and Exchange Commission, Office of Investor Education and Assistance, Uniswap developer documentation. From Liquidity, order books and slippage.
Bad debt: A loan worth more than its collateral, so liquidating it cannot repay it in full. Source: Aave Protocol Documentation, Aave Protocol Documentation. From Lending, borrowing and liquidations.
Bank run: Many depositors pulling their money out at once because they fear the bank may fail. Source: New York State Department of Financial Services (DFS), Board of Governors of the Federal Reserve System, with a cover letter from Vice Chair for Supervision Michael S. Barr. From Banking and crypto.
Bankruptcy remoteness: A design that keeps an SPV's assets away from the sponsor's creditors if the sponsor goes bankrupt. Source: The Joint Forum (Basel Committee, IOSCO and IAIS), Bank for International Settlements. From Real-world assets.
Base fee: The lowest price per unit of gas a block accepts. The network sets it, and it is burned. Source: ethereum.org developer docs, Ethereum Improvement Proposals (Vitalik Buterin and others). From Transactions, gas and fees.
Beneficial owner: For a US bank's company customer: each person who owns 25% or more of the company, plus one person who controls or manages it. Source: Electronic Code of Federal Regulations (US Department of the Treasury, FinCEN rules), read 22 October 2026. From Banking and crypto.
Beneficial owner: Under Cayman's Beneficial Ownership Transparency Act, an individual who owns or controls 25% or more of the shares or votes, or otherwise has ultimate effective control. Source: Cayman Islands Government, Legislation Gazette (copy hosted by the Cayman Islands Monetary Authority). From Cayman foundation companies.
Beneficiary: A person who will or may benefit from a foundation company carrying out its objects. Unless the constitution says otherwise, a beneficiary has no rights over the company. Source: Cayman Islands Government, Legislation Gazette, Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Bid: The highest price a buyer will pay right now. Source: Investor.gov, US Securities and Exchange Commission. From Market makers: loan or retainer?.
Bid-ask spread: The gap between the highest price a buyer will pay (the bid) and the lowest price a seller will accept (the ask). Source: Investor.gov, US Securities and Exchange Commission. From Liquidity, order books and slippage.
BIP-39: The standard that turns 128 to 256 random bits, plus a checksum, into words from a list of 2,048. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
BitLicense: New York's licence for virtual currency business activity, under regulation 23 NYCRR Part 200 (issued June 2015). Source: New York State Department of Financial Services (read 22 October 2026). From The rules: acts and regulators.
Blind signing: Approving something your wallet can't show in readable form, such as a raw hash. Ledger compares it to signing a blank cheque. Source: Ledger Academy (hardware-wallet maker's documentation). From Wallets, keys and seed phrases.
Blob: A cheaper, short-lived type of data that rollups post to Ethereum, added by EIP-4844. Source: ethereum.org, ethereum.org developer docs. From Layer 2s and bridges.
Block: A batch of transactions plus a header that describes it, including the hash of the block before. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone). From How a blockchain works.
Block confirmation: A count of how far a transaction is buried. Each new block on top adds one. More confirmations make a transaction safer to rely on. Source: Etherscan Information Center, Bitcoin Developer Documentation (developer.bitcoin.org). From Reading the chain.
Block explorer: A website that searches a blockchain's public records and shows transactions, addresses, blocks and tokens in readable form. It can't change the chain. Source: Etherscan Information Center, Etherscan Information Center. From Reading the chain.
Block subsidy: The new bitcoin a miner may create in a block. It started at 50 BTC and has been 3.125 BTC since April 2024. Source: Bitcoin Developer Documentation (developer.bitcoin.org), Bitcoin.org. From Bitcoin.
Blockchain: A shared digital ledger where transactions are grouped into blocks, and each block is linked to the one before it. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby and Scarfone). From Welcome to Web3.
Bounty: A reward for one clearly defined task, paid when the work is accepted. Source: Gitcoin, mechanisms library (read 22 October 2026). From Ecosystem grants.
Bridge: A link between blockchains that lets tokens and messages pass from one to another. Source: ethereum.org. From Layer 2s and bridges.
Bundler: Under ERC-4337, a node that collects UserOperations and packs them into one real transaction. Source: Ethereum Improvement Proposals (V. Buterin, Y. Weiss, D. Tirosh and others). From Multisig and smart accounts.
Burn: Destroying ETH so that nobody receives it. The base fee is burned. Source: Ethereum Improvement Proposals (Vitalik Buterin and others), ethereum.org developer docs. From Transactions, gas and fees.
Burn: Removing tokens for good, usually by sending them to an address nobody controls. Source: CoinMarketCap Academy, figures pulled by CoinMarketCap on 7 October 2026, ethereum.org (read again 24 October 2026). From Tokenomics, vesting and unlocks.
Bylaws: Extra rules a constitution can provide for. Directors must follow them as far as the law and the constitution allow, but they are not part of the constitution. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Bytecode: Low-level machine instructions. Smart contract code is compiled into bytecode so the EVM can run it. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Call option: The right to buy something at a fixed price in the future. Source: Ruizhe Jia, Berkeley RDI DeFi course. From Market makers: loan or retainer?.
CASP (crypto-asset service provider): Under MiCA, a firm whose business is providing crypto-asset services to clients professionally, and that is allowed to do so under Article 59. Source: European Parliament and Council of the European Union, Official Journal L 150, 9 June 2023 (read on EUR-Lex; the original text, not later amendments). From The rules: acts and regulators.
Centralised exchange (CEX): A company-run trading platform for buying and selling crypto, for ordinary money or other crypto. It acts as a middleman and often holds customers' assets. Source: Bank for International Settlements, ethereum.org (read 22 October 2026). From Exchanges, DEXs and AMMs.
Challenge period: The time, roughly seven days, when anyone can challenge an optimistic rollup batch. Source: ethereum.org developer docs. From Layer 2s and bridges.
Change output: The part of a transaction that sends the leftover back to the sender, because inputs can't be partly spent. Source: Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub, Bitcoin Developer Documentation (developer.bitcoin.org). From Bitcoin.
Change output: An output that sends the leftover of a Bitcoin payment back to the sender. Source: Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Reading the chain.
Checksum: Extra information added to an address or phrase so that software can spot most typing mistakes. Source: Ethereum Improvement Proposals (eips.ethereum.org), Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
CID: A content identifier in IPFS: an address made from the content itself, so any change to the file gives a new CID. Source: IPFS Docs. From NFTs.
CIMA: The Cayman Islands Monetary Authority, which registers and licenses virtual asset service providers under the VASP Act. Source: Cayman Islands Government, legislation.gov.ky (revised as at 31 December 2023), Cayman Islands Monetary Authority (CIMA), supervisory circular. From The rules: acts and regulators.
Circulating supply: The tokens available in the market now. It leaves out locked, reserved and burned tokens. Source: CoinMarketCap Academy, CoinGecko (the live page asked for a browser check; read via the Wayback Machine copy of 8 October 2026). From Tokenomics, vesting and unlocks.
Clawback: Taking back grant funds or locked tokens when terms are broken or key milestones are missed. Source: Optimism Collective governance forum (post last edited 8 May 2025; read 22 October 2026). From Ecosystem grants.
Cliff: A date before which no tokens vest. In OpenZeppelin's code, the months before it vest all at once on that date. Source: OpenZeppelin Contracts 5.x documentation (read 22 October 2026), OpenZeppelin Contracts on GitHub, master branch (read 22 October 2026). From Tokenomics, vesting and unlocks.
Close factor: The most of a loan that can be repaid in a single liquidation. Source: Compound v2 documentation, Aave (blog). From Lending, borrowing and liquidations.
Code audit: An independent review of a smart contract's code to find weaknesses. It won't catch every bug. Source: FBI Internet Crime Complaint Center, ethereum.org developer docs. From Security and common attacks.
Cold wallet: A wallet kept off the internet, usually a physical device or even paper. Safer from online attacks, but it can be lost or stolen. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov). From Self-custody.
Collateral: Assets locked up as security for a loan. If the loan is not repaid, the lender can take them. Source: Aave Protocol Documentation, ethereum.org. From Lending, borrowing and liquidations.
Collateral chain: Using borrowed tokens as collateral for another loan. It makes leverage in DeFi hard to measure. Source: Bank for International Settlements (Sirio Aramonte, Sebastian Doerr, Wenqian Huang and Andreas Schrimpf), Financial Stability Board. From Lending, borrowing and liquidations.
Company limited by guarantee: A company whose members promise to pay up to a set amount if it is wound up. It may, but need not, also have share capital. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Concentrated liquidity: Uniswap v3's design, where each liquidity provider chooses a price range and earns fees only while the price is inside it. Source: Hayden Adams, Noah Zinsmeister, Moody Salem, River Keefer and Dan Robinson, Uniswap Developers documentation (read 22 October 2026). From Exchanges, DEXs and AMMs.
Concentration: Holding a large share of a treasury in one asset, or with one bank, platform or protocol. Source: Blockchain Research Lab, ENS DAO governance documents (posted on the ENS forum on 8 May 2026; status: passed, in a Snapshot vote held from 24 to 29 June 2026). From Treasury and runway.
Confirmation: On Bitcoin, a transaction gains one confirmation for each block, starting with the block that includes it. Source: Bitcoin developer documentation (developer.bitcoin.org). From How a blockchain works.
Constant product formula: Uniswap's rule x × y = k: the product of a pool's two reserves must not fall after a trade. Source: Uniswap Developers documentation (read 22 October 2026), Hayden Adams, Noah Zinsmeister and Dan Robinson. From Exchanges, DEXs and AMMs.
Constitution: A foundation company's memorandum and articles of association, but not its bylaws. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Contract account: An Ethereum account controlled by its smart contract code. It has no private key. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Correspondent banking: When one bank holds deposits for other banks and provides payment services to them. Source: Committee on Payments and Market Infrastructures (CPMI), Bank for International Settlements. From Banking and crypto.
Cost basis: What an asset cost to acquire. For crypto bought with cash, PwC says this is the cash paid, including transaction costs. The realised gain or loss is the sale price minus the cost basis of what was sold. Source: PwC US National Office (Viewpoint), Deloitte (DART). From Crypto accounting basics.
Cost basis: What you paid for an asset, including the fees for buying it. It is taken away from what you get when you sell, to find the gain or loss. Source: US Internal Revenue Service (IRS), US Internal Revenue Service (IRS). From Crypto tax basics.
Cost-less-impairment model: The older US model for crypto: hold it at cost, write it down when its value falls, and never write it back up until it is sold. Source: Financial Accounting Standards Board (FASB). Read from the FASB's own file store, because fasb.org refused our automated download. From Crypto accounting basics.
Crypto-Asset Reporting Framework (CARF): An OECD standard under which crypto firms report users' transactions each year, and tax authorities share the data with each other. Source: OECD Global Forum on Transparency and Exchange of Information for Tax Purposes. From Crypto tax basics.
Crypto-asset white paper: The disclosure document MiCA requires before most crypto-assets are offered to the public in the EU. No authority approves it in advance. Source: European Parliament and Council of the European Union, Official Journal L 150, 9 June 2023 (read on EUR-Lex; the original text, not later amendments). From The rules: acts and regulators.
Custodian: A firm that keeps assets safe on behalf of others. Source: Financial Stability Board, Bank for International Settlements and Committee on Payments and Market Infrastructures, report to the G20. From Real-world assets.
Custody: Holding the keys that control crypto. An exchange that holds the keys to your coins has custody of them. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (staff views), ethereum.org (read 22 October 2026). From Exchanges, DEXs and AMMs.
Custody risk: The risk of losing assets held for you because the holder goes bust, is careless, commits fraud or keeps poor records. Source: Bank for International Settlements and Committee on Payments and Market Infrastructures, report to the G20. From Treasury and runway.
Customer due diligence (CDD): The checks a bank or exchange runs on a customer: who they are, who owns them, why they want the account, and ongoing monitoring. Source: Financial Action Task Force (FATF), updated June 2026, Electronic Code of Federal Regulations (US Department of the Treasury, FinCEN rules), read 22 October 2026. From Banking and crypto.
Cut-off: Recording each transaction in the correct accounting period. Auditors test it, and EY says crypto reconciliations should include adequate cut-off procedures. Source: ACCA (Association of Chartered Certified Accountants), student resources, EY (Ernst & Young LLP), AccountingLink. From Crypto accounting basics.
DAO: A collectively-owned organisation run by proposals and votes, whose treasury can't be spent without the group's approval. Source: ethereum.org (page last updated 26 June 2026). From Ecosystem grants.
DAO (decentralised autonomous organisation): A group that makes decisions through proposals and votes, with its rules and treasury held in smart contracts. Source: ethereum.org (page last updated 26 June 2026; read 24 October 2026). From DAOs and governance.
DAO (decentralised autonomous organisation): A group that makes decisions through votes by holders of its token, often with no formal corporate structure. Source: US District Court for the Northern District of California (copy on CourtListener). From Cayman foundation companies.
DAO LLC: A Wyoming limited liability company whose articles say it is a decentralized autonomous organization. Source: Wyoming Legislature, 2021 General Session. From DAOs and governance.
De-risking: Ending or restricting relationships with whole groups of customers to avoid risk, instead of managing each customer's risk. Source: Financial Action Task Force (FATF), US Department of the Treasury. From Banking and crypto.
Debit and credit: The two sides of every account: debits on the left, credits on the right. An increase in an asset is a debit; an increase in a liability is a credit. Source: US Internal Revenue Service (IRS), ACCA (Association of Chartered Certified Accountants), student resources. From Crypto accounting basics.
Decentralised exchange (DEX): A trading app built from smart contracts, where people swap tokens directly from their own wallets and prices are set by formulas. Source: Bank for International Settlements, ethereum.org (read 22 October 2026). From Exchanges, DEXs and AMMs.
Decentralised oracle network: A group of independent oracle nodes that agree on a value before it goes on-chain. Source: ethereum.org developer docs, Chainlink Labs (Lorenz Breidenbach and others). From Oracles.
Decimals: A token setting that says where the decimal point goes. Divide the raw number by 10 to the power of decimals to get the amount people see. Source: OpenZeppelin Contracts 5.x documentation, Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin). From Reading the chain.
Decimals: How many decimal places a token shows. The contract stores whole numbers; divide by 10 to the power of decimals to get the amount people see. Source: Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin), OpenZeppelin Contracts 5.x documentation. From Token standards.
Delegate: An address that votes with the voting power that token holders have assigned to it. Source: ethereum.org (page last updated 26 June 2026; read 24 October 2026), Arbitrum DAO governance documentation, public preview (read 24 October 2026). From DAOs and governance.
Delegate call: A call that runs another contract's code as if it were the calling contract's own. Safe's help centre calls it dangerous in an ordinary transaction. Source: Sygnia (a security firm that examined the Bybit signers' computers), Safe Help Center (Safe Knowledge Base). From Multisig and smart accounts.
Delegation: Assigning your tokens' voting power to another address, or to your own, without moving the tokens. Source: Uniswap developer documentation (read 24 October 2026), OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Depeg: When a stablecoin's market price moves away from its peg, for example a dollar stablecoin trading at 90 cents. Source: Board of Governors of the Federal Reserve System (Cy Watsky and others), Bank for International Settlements. From Stablecoins.
Deposit insurance: Protection for bank deposits if a bank fails. The FDIC's standard limit is $250,000 per depositor, per insured bank, for each account ownership category. Source: Federal Deposit Insurance Corporation (FDIC), read 22 October 2026. From Banking and crypto.
Deposit insurance: Government cover for bank deposits if a bank fails. In the US it covers $250,000 per depositor, per insured bank, per ownership category, and not crypto. Source: Federal Deposit Insurance Corporation (FDIC), read 24 October 2026. From Treasury and runway.
Derivation path: The address of one key in an HD wallet's tree, such as m/44'/60'/0'/0/0. It names the purpose, coin type, account, change chain and address index. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
Deviation threshold: How far, in percent, the outside price must move from the on-chain price before a feed updates. Source: Chainlink documentation. From Oracles.
DEX aggregator: A service that compares prices across many DEXs and can split one swap between them. Source: 1inch Learn (read 22 October 2026). From Exchanges, DEXs and AMMs.
Digital asset: The IRS's term for a record of value kept on a cryptographically secured ledger, such as a blockchain. It includes cryptocurrencies, stablecoins and NFTs. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Digital signature: Proof, made with a private key, that the key's owner approved exactly this data. Anyone can check it, and checking it doesn't reveal the key. Source: Andreas M. Antonopoulos, Gavin Wood and co-authors (CC BY-NC-ND 4.0 for its first 12 months, then CC BY-SA 4.0), GitHub, Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Wallets, keys and seed phrases.
Disposal: Getting rid of crypto in any way, such as selling it, swapping it, spending it or giving it away. A disposal can give a gain or a loss. Source: HM Revenue & Customs (HMRC), Cryptoassets Manual, US Internal Revenue Service (IRS). From Crypto tax basics.
Dominion and control: The point when you can sell, swap or otherwise dispose of crypto you received. The IRS counts staking rewards as income from then. Source: US Internal Revenue Service (IRS), US Internal Revenue Service (IRS). From Crypto tax basics.
Double spending: Spending the same digital money more than once. Digital money is easy to copy, so a system has to stop this. Source: Bank for International Settlements. From Welcome to Web3.
Double-entry bookkeeping: A way of keeping books in which every transaction is recorded as a debit in one account and a credit in another, so total debits always equal total credits. Source: US Internal Revenue Service (IRS). From Crypto accounting basics.
Double-spending: Paying with the same digital money twice. Bitcoin was designed to stop it without a bank in the middle. Source: Satoshi Nakamoto (the Bitcoin whitepaper), Bitcoin Developer Documentation (developer.bitcoin.org). From Bitcoin.
E-money token: Under MiCA, a crypto-asset that aims to keep a stable value by referencing the value of one official currency. Source: European Parliament and Council of the European Union, Official Journal L 150, 9 June 2023 (read on EUR-Lex; the original text, not later amendments). From The rules: acts and regulators.
E-money token (EMT): Under EU law, a crypto-asset that aims to keep a stable value by referencing one official currency. Source: European Parliament and Council of the European Union, Official Journal of the European Union (EUR-Lex). From Stablecoins.
Economic substance notification (ESN): The yearly notice every Cayman company gives the Tax Information Authority, saying whether it carries on a relevant activity. Source: Cayman Islands Government, Legislation Gazette, Cayman Islands Department for International Tax Cooperation. From Cayman foundation companies.
Ecosystem grant: Money or other support that a blockchain's foundation or DAO gives to people building things for its network. Source: Ethereum Foundation, Ecosystem Support Program (read 22 October 2026), Arbitrum Foundation (read 22 October 2026). From Ecosystem grants.
Effective gas price: The price actually paid per unit of gas: the base fee plus the tip. Source: ethereum.org developer docs. From Reading the chain.
EIP-55: An Ethereum standard that hides a checksum in which letters of an address are capitals. Source: Ethereum Improvement Proposals (eips.ethereum.org). From Wallets, keys and seed phrases.
EIP-7702: A 2025 change that lets an ordinary account point to smart contract code. The account's private key still keeps full control. Source: ethereum.org, ethereum.org roadmap. From Multisig and smart accounts.
Emissions: New tokens created on a schedule, for example as staking rewards. Source: CoinMarketCap Academy, figures pulled by CoinMarketCap on 7 October 2026, ethereum.org (read again 24 October 2026). From Tokenomics, vesting and unlocks.
Entropy: The random bits a wallet starts from. A 12-word BIP-39 phrase carries 128 bits. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
ERC: Short for Ethereum Request for Comments. A category of Ethereum Improvement Proposal for application-level standards, such as token standards. Source: Ethereum Improvement Proposals (Martin Becze, Hudson Jameson and others), ethereum.org developer docs. From Token standards.
ERC-1155: A multi-token standard: one contract can hold fungible tokens, NFTs, or a mix. Source: Ethereum Improvement Proposals (Radomski, Cooke, Castonguay and others). From NFTs.
ERC-721: An Ethereum standard for NFTs. Each token is tracked separately, and each token ID has exactly one owner, so a wallet holds none or one of it. Source: Ethereum Improvement Proposals (Entriken, Shirley, Evans and Sachs). From NFTs.
Ethereum Virtual Machine (EVM): The one shared computer that every Ethereum node keeps a copy of and agrees on. It runs smart contracts. Source: ethereum.org developer docs, ethereum.org developer docs. From Ethereum and smart contracts.
Event log: A record a smart contract writes while it runs, for apps outside the chain to read. Explorers show logs on a Logs tab. Source: Etherscan Information Center. From Reading the chain.
Exempted company: A Cayman company registered as exempted because its objects are to be carried out mainly outside the Cayman Islands. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Exit queue: The rate-limited wait to stop staking. How long it takes depends on how many others are leaving at the same time. Source: ethereum.org (read 24 October 2026; page last updated 17 August 2026), ethereum.org (read 24 October 2026). From Staking and yield.
Externally-owned account (EOA): An Ethereum account controlled by whoever holds its private keys. It can start transactions. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Externally-owned account (EOA): An ordinary Ethereum account controlled by a private key. With the key you can do anything; without it, nothing. Source: ethereum.org. From Wallets, keys and seed phrases.
Fair market value: What crypto is worth in dollars at a given moment. For a coin traded on an exchange, it is found by converting at the exchange rate. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Fair value: The price you would receive to sell an asset in an orderly transaction between market participants on the measurement date. It is an exit price. Source: Financial Accounting Standards Board (FASB). Read from the FASB's own file store, IFRS Foundation (read 24 October 2026). From Crypto accounting basics.
FATF (Financial Action Task Force): An independent inter-governmental body whose Recommendations are recognised as the global standard against money laundering and terrorist financing. Source: Financial Action Task Force (FATF). From The rules: acts and regulators.
Fedwire: The US Federal Reserve's system for large, time-critical payments between banks with a Fed account. A payment is final once processed. Source: Board of Governors of the Federal Reserve System, read 22 October 2026. From Banking and crypto.
Fee rate: A transaction's fee divided by its size, usually in sats per virtual byte (sat/vB). Source: Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub, mempool.space (open-source block explorer). From Bitcoin.
Fiat money: Money the central bank won't convert into gold or any other asset. Bank of England money has been fiat money since 1931. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
FIFO (first in, first out): A cost method that treats the units bought first as the first ones sold. Source: US Internal Revenue Service (IRS), Financial Accounting Standards Board (FASB). Read from the FASB's own file store. From Crypto accounting basics.
Finality: The point at which a transaction is in a block that can no longer change. Source: ethereum.org developer docs, ethereum.org developer docs. From How a blockchain works.
Flash loan: A loan taken out and paid back within the same transaction. Source: ethereum.org. From Oracles.
Flash loan: A loan with no collateral that must be borrowed and repaid within one transaction. Source: Aave Protocol Documentation, Financial Stability Board. From Lending, borrowing and liquidations.
Flash loan: A loan of tokens that is borrowed and paid back within a single transaction. Source: Immunefi, a security firm (article by one of its smart contract triagers). From DAOs and governance.
Form 1099-DA: The US form brokers use to report customers' crypto sales to the IRS, starting with sales on or after 1 January 2025. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Foundation company: A Cayman company that the Registrar has declared to be a foundation company under section 5 of the Foundation Companies Act. Source: Cayman Islands Government, Legislation Gazette, Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Fraud proof: Evidence, checked on Ethereum, that a rollup batch was worked out wrongly. Source: ethereum.org developer docs. From Layer 2s and bridges.
Full node: A node that stores the blockchain and checks that transactions and blocks are valid. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone), Bitcoin Project, bitcoin.org. From How a blockchain works.
Fully diluted valuation (FDV): A token's price times its total or max supply, as if every token were already in circulation. Sites differ on which supply they use. Source: CoinGecko Learn (read via the Wayback Machine copy of 13 July 2026), CoinMarketCap Academy, CoinMarketCap Academy, figures pulled by CoinMarketCap on 7 October 2026. From Tokenomics, vesting and unlocks.
Fungible: Interchangeable: every unit is exactly the same, in type and value, as every other unit. Source: ethereum.org developer docs, Ethereum Improvement Proposals (William Entriken, Dieter Shirley, Jacob Evans, Nastassia Sachs). From Token standards.
Gas: The unit that measures how much computing work an action on Ethereum needs. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Gas: The unit that measures how much computing work an action on Ethereum needs. Source: ethereum.org developer docs. From Transactions, gas and fees.
Gas limit: The most gas a transaction is allowed to use. Source: ethereum.org developer docs, ethereum.org developer docs. From Transactions, gas and fees.
Gas used: The exact units of gas a transaction used. An explorer multiplies it by the gas price to show the fee. Source: Etherscan Information Center. From Reading the chain.
Genesis block: The first block in a blockchain. It has no block before it. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone). From How a blockchain works.
Governance token: A token that gives its holder voting power in a DAO, usually in proportion to how many tokens they hold. Source: ethereum.org (page last updated 26 June 2026; read 24 October 2026), Compound documentation (v2, read 24 October 2026). From DAOs and governance.
Grey list: The name often used for FATF's list of jurisdictions under increased monitoring, which are working with FATF to fix strategic weaknesses. Source: Financial Action Task Force (FATF), Financial Action Task Force (FATF). From The rules: acts and regulators.
Gwei: A tiny unit of ETH. 1 ETH is 1,000,000,000 gwei. Source: ethereum.org developer docs, ethereum.org. From Transactions, gas and fees.
Halving: The cut in half of the block subsidy every 210,000 blocks, roughly every four years. Source: Bitcoin.org, Bitcoin Core project, GitHub. From Bitcoin.
Hard fork: A change to a blockchain's rules that permanently splits it, which can create a new coin alongside the old one. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Hardware wallet: A small device built only to be a wallet. It keeps private keys offline, away from the internet. Source: Bitcoin.org, ethereum.org. From Self-custody.
Hash: The result of scrambling any amount of data into a short, fixed-size output. Source: Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Bitcoin.
Hash function: A function that turns data of almost any size into a short code of fixed length, called a digest. Source: US National Institute of Standards and Technology, Computer Security Resource Center, US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone). From How a blockchain works.
HD wallet: A hierarchical deterministic wallet: one seed grows a whole tree of keys, so one backup covers them all. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
Health factor: Aave V3's safety measure for a loan: collateral value times liquidation threshold, divided by debt. Below 1, the loan can be liquidated. Source: Aave (Aave Help), Aave Protocol Documentation. From Lending, borrowing and liquidations.
Heartbeat: The set time after which a feed starts an update even if the price has not moved. Source: Chainlink documentation, Chainlink documentation. From Oracles.
Holding period: How long you held an asset. In the US it starts the day after you got it and ends on the day you sell or swap it. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Hot wallet: A wallet connected to the internet, such as a phone or web app. Convenient, but exposed to online attacks. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov). From Self-custody.
Identity registry: In ERC-3643, the list linking each approved investor's wallet to an identity contract and a country code. Transfers to wallets not on it fail. Source: Ethereum Improvement Proposals (Joachim Lebrun, Tony Malghem, Kevin Thizy, Luc Falempin, Adam Boudjemaa). From Token standards.
Impairment: Writing an asset down because its carrying amount is more than the amount that can be recovered from it. Source: IFRS Foundation (read 24 October 2026). From Crypto accounting basics.
Impermanent loss: How much less a liquidity provider's share is worth than simply holding the same tokens, after prices move. It disappears if prices return. Source: Uniswap Developers documentation (read 22 October 2026; rechecked 24 October 2026). The formula, the table and the term “impermanent loss” sit inside the page's quotation of an outside article it links to on Medium. From Exchanges, DEXs and AMMs.
Inactivity leak: An Ethereum emergency rule that slowly drains the stake of offline validators until the active ones hold more than two-thirds of it. Source: ethereum.org developer documentation (read 24 October 2026; page last updated 28 September 2026). From Staking and yield.
Input data: Extra data sent with a transaction, most often the function call for a smart contract. Source: Etherscan Information Center. From Reading the chain.
Interested person: A member or supervisor, someone with the right to become one, or anyone the constitution declares to be one. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Internal transaction: ETH moved by a smart contract as part of a transaction someone else started. Source: Etherscan Information Center, Blockscout documentation. From Reading the chain.
Interval fund: A fund that offers to buy back only a set share of its shares, 5% to 25%, at set times. Source: Investor.gov, US Securities and Exchange Commission. From Real-world assets.
Inventory risk: The risk of holding something you can't sell. Source: Presto Research (Min Jung). From Market makers: loan or retainer?.
Investment contract (Howey test): In US law, an investment of money in a common enterprise with an expectation of profits from the efforts of others. It is a security. Source: Supreme Court of the United States (Library of Congress copy of the United States Reports), US Securities and Exchange Commission, with guidance from the Commodity Futures Trading Commission. From The rules: acts and regulators.
Investment policy statement (IPS): A written policy that sets a treasury's goals, risk limits, allowed assets, roles and reporting. Source: ENS DAO governance documents (posted on the ENS forum on 8 May 2026; status: passed, in a Snapshot vote held from 24 to 29 June 2026). From Treasury and runway.
IOU: A promise to pay someone back at a later date. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
Issuance: Creating new coins that did not exist before. On proof-of-stake networks, new coins are paid to validators as rewards. Source: ethereum.org (read 24 October 2026; page last updated 6 June 2026), US Securities and Exchange Commission, Division of Corporation Finance. From Staking and yield.
Kink (optimal utilisation): The point on a rate curve above which the borrow rate rises much faster. Source: Compound III documentation, Aave Protocol Documentation. From Lending, borrowing and liquidations.
KYC (know your customer): The identity checks a firm runs on you before it opens your account. Source: Franklin Templeton Trust, filed with the US Securities and Exchange Commission, World Economic Forum, in collaboration with Accenture. From Real-world assets.
KYC (know your customer): Identity checks a funder runs before paying. For a company, they can include proof of incorporation. Source: Gitcoin support knowledge base, written for its 15th grants round, GR15 (read 22 October 2026), Arbitrum DAO governance forum (post last edited 15 July 2025). From Ecosystem grants.
Layer 2: A network built on top of Ethereum that offers lower fees. Source: ethereum.org. From Transactions, gas and fees.
Layer 2: A separate blockchain that extends Ethereum and settles its transactions on Ethereum. Source: ethereum.org. From Layer 2s and bridges.
Ledger: A collection of transactions: a record of who paid what to whom. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby and Scarfone). From Welcome to Web3.
Lending pool: A set of smart contracts holding tokens that lenders supply and borrowers borrow from. Source: ethereum.org, Aave Protocol Documentation. From Lending, borrowing and liquidations.
Lightning Network: A network of two-party payment channels. Payments move off the main chain, and only opening and closing a channel go on it. Source: Joseph Poon and Thaddeus Dryja, Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Bitcoin.
Limit order: An order to buy or sell only at a set price or better. It protects the price, but may not fill. Source: Investor.gov, US Securities and Exchange Commission, Office of Investor Education and Assistance. From Liquidity, order books and slippage.
Liquid staking token (LST): A receipt token for coins staked through a pool, which can be traded or used while the coins stay staked. Source: ethereum.org (read 24 October 2026; page last updated 17 August 2026), US Securities and Exchange Commission, Division of Corporation Finance. From Staking and yield.
Liquidation: Repaying part or all of an under-collateralised loan with the borrower's collateral, done by outside liquidators or the protocol. Source: Aave (Aave Help), Compound III documentation. From Lending, borrowing and liquidations.
Liquidation: Selling a vault's collateral, usually by auction, to repay its stablecoin debt and a penalty. Source: MakerDAO, now Sky (white paper first published February 2020; read 22 October 2026), Sky Protocol developer documentation, read 22 October 2026. From Stablecoins.
Liquidation bonus: Extra collateral a liquidator receives on top of the value of the debt it repays. It is the borrower's cost. Source: Aave Protocol Documentation, Compound v2 documentation. From Lending, borrowing and liquidations.
Liquidation ratio: The collateral-to-debt ratio below which a vault can be liquidated. Source: MakerDAO, now Sky (white paper first published February 2020; read 22 October 2026). From Stablecoins.
Liquidation threshold: The percentage of collateral value at which a loan counts as under-collateralised and can be liquidated. It is set above the LTV on Aave V3. Source: Aave, aave/risk-v3 repository on GitHub, Aave Protocol Documentation. From Lending, borrowing and liquidations.
Liquidity: How easily you can buy or sell something quickly, without moving its price much. Source: Investor.gov, US Securities and Exchange Commission, Bank for International Settlements (Claudio Borio). From Liquidity, order books and slippage.
Liquidity pool: The two token reserves held by an AMM's smart contract, which traders swap against. Source: Uniswap Developers documentation (read 22 October 2026), ethereum.org (read 22 October 2026). From Exchanges, DEXs and AMMs.
Liquidity provider (LP): Anyone who deposits both tokens of a pair into a pool, in return for a share of the trading fees. Source: Uniswap Developers documentation (read 22 October 2026), Uniswap Developers documentation (read 22 October 2026). From Exchanges, DEXs and AMMs.
Loan-to-value (LTV): The most you can borrow, as a percentage of your collateral's value. At 75%, $1,000 of collateral lets you borrow $750. Source: Aave Protocol Documentation. From Lending, borrowing and liquidations.
Lock-up: A rule that stops holders selling for a set time. For company shares, most last 180 days. Source: Investor.gov, US Securities and Exchange Commission. From Tokenomics, vesting and unlocks.
Lock-up: An agreement that stops holders selling for a set time. Source: Investor.gov, US Securities and Exchange Commission (read 24 October 2026), Optimism Foundation, Optimism governance forum. From Treasury and runway.
Lock-up: A rule that you may not sell tokens you received for a set time. Optimism's grant policies set one year for most Governance Fund grants. Source: Optimism Collective governance forum (post last edited 8 May 2025; read 22 October 2026). From Ecosystem grants.
Long-term capital gain: In the US, a gain on an asset held for more than one year. A lower rate may apply to it than to short-term gains, which are taxed as ordinary income. Source: US Internal Revenue Service (IRS). From Crypto tax basics.
Low float: Binance Research's term for tokens that launch with only a small part of their supply in circulation. Source: Binance Research. From Tokenomics, vesting and unlocks.
LP token: A token that records a liquidity provider's share of a pool. It can be handed back for that share of the reserves and fees. Source: ethereum.org (read 22 October 2026), Uniswap Developers documentation (read 22 October 2026). From Exchanges, DEXs and AMMs.
Maker and taker: A maker order waits on the order book. A taker order fills at once against orders already there. Many exchanges charge the two different fees. Source: Coinbase Developer Documentation, Coinbase Exchange (read 22 October 2026), Kraken (read 22 October 2026; rechecked 24 October 2026; the fee table sits under the page's “Kraken Pro” heading). From Exchanges, DEXs and AMMs.
Market cap: A token's price times its circulating supply. Source: CoinGecko (the live page asked for a browser check; read via the Wayback Machine copy of 8 October 2026), CoinMarketCap Academy, figures pulled by CoinMarketCap on 7 October 2026. From Tokenomics, vesting and unlocks.
Market depth: How big a trade a market can absorb without the price moving; often measured by the orders waiting at the best prices. Source: Bank for International Settlements (Claudio Borio), Board of Governors of the Federal Reserve System. From Liquidity, order books and slippage.
Market maker: A firm that stands ready to buy and sell at prices it shows to everyone. Source: Investor.gov, US Securities and Exchange Commission. From Market makers: loan or retainer?.
Market order: An order to buy or sell straight away at the best price available. It almost always fills, but the price is not guaranteed. Source: Investor.gov, US Securities and Exchange Commission, Office of Investor Education and Assistance, Investor.gov, US Securities and Exchange Commission. From Liquidity, order books and slippage.
Marketplace: A website for buying and selling NFTs, which usually takes a percentage of each sale. Source: US Patent and Trademark Office and US Copyright Office. From NFTs.
Matching pool: Money that sponsors put up for a quadratic funding round, shared among projects on top of what donors give. Source: Gitcoin, mechanisms library, Gitcoin (read 22 October 2026). From Ecosystem grants.
Max fee: The most you will pay per unit of gas, base fee and tip included. Source: ethereum.org developer docs. From Transactions, gas and fees.
Max supply: The most tokens that can ever exist, minus any burned. Some tokens, such as ether, have none. Source: CoinMarketCap Academy (read 22 October 2026), CoinMarketCap Academy. From Tokenomics, vesting and unlocks.
Medium of exchange: Something people hold because they plan to swap it for something else, not because they want it for itself. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
Mempool: A node's queue of transactions waiting to be added to a block. Source: mempool.space (open-source block explorer). From Bitcoin.
Metadata: Information about a token, such as its name, description and image. ERC-721 points to it with a link from the tokenURI function. Source: Ethereum Improvement Proposals (William Entriken, Dieter Shirley, Jacob Evans, Nastassia Sachs). From Token standards.
Metadata: Details about an NFT, such as its name, a description and a link to its image, usually kept in a JSON file. Source: Ethereum Improvement Proposals (Entriken, Shirley, Evans and Sachs), IPFS Docs. From NFTs.
Method ID: The first 4 bytes of the input data. They pick which contract function to run. Also called the function selector. Source: Etherscan Information Center, ethereum.org developer docs. From Reading the chain.
MEV: Maximal extractable value: profit taken by including, leaving out or reordering transactions in a block. Source: ethereum.org developer docs. From Liquidity, order books and slippage.
MEV (maximal extractable value): Extra value a block producer can take by choosing which transactions go into a block, and in what order. Source: Lido documentation (read 24 October 2026). From Staking and yield.
MiCA: The EU's Markets in Crypto-Assets Regulation, Regulation (EU) 2023/1114. It sets uniform EU market rules for crypto-assets. Source: European Parliament and Council of the European Union, Official Journal L 150, 9 June 2023 (read on EUR-Lex; the original text, not later amendments), European Securities and Markets Authority (ESMA), read 22 October 2026. From The rules: acts and regulators.
Mid price: The price halfway between the best bid and the best ask. A useful reference, but on an order book every trade matches a bid or an ask. Source: Chainlink documentation. From Liquidity, order books and slippage.
Milestone: An agreed piece of work, with a deadline and a test of when it is done, that releases a slice of a grant once a reviewer accepts it. Source: Gitcoin, mechanisms library (read 22 October 2026). From Ecosystem grants.
Mining: Spending computing power to process transactions, secure the network and add the next block, in return for a reward. Source: Bitcoin.org, Bitcoin Developer Documentation (developer.bitcoin.org). From Bitcoin.
Mint: To create new units of a token. On Solana, a token's mint account also stores its supply, decimals and who may create more. Source: Solana Program Library documentation (spl.solana.com/token now redirects here), Solana documentation, Solana Foundation. From Token standards.
Mint: To create a new NFT by publishing a new token to a blockchain. Source: US Patent and Trademark Office and US Copyright Office, ethereum.org. From NFTs.
Mint and burn: Minting creates new tokens when someone pays in; burning destroys tokens when they are redeemed. Source: Board of Governors of the Federal Reserve System (Garth Baughman, Francesca Carapella, Jacob Gerszten and David Mills), Board of Governors of the Federal Reserve System (Cy Watsky and others). From Stablecoins.
Money: A special kind of IOU that everyone trusts other people will accept in exchange for goods and services. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
Money market fund: A fund that invests in liquid, short-term debt, cash and cash equivalents. Source: Investor.gov, US Securities and Exchange Commission. From Real-world assets.
Money transmitter: In US federal rules, a business that accepts currency, funds or value that substitutes for currency from one person and transmits it to another location or person. Source: Financial Crimes Enforcement Network (FinCEN), US Department of the Treasury. From The rules: acts and regulators.
MPC (secure multiparty computation): A way for several parties to work out a result together without showing each other their secret inputs, such as shares of a key. Source: US National Institute of Standards and Technology (NIST), Computer Security Resource Center, L. Brandão, N. Mouha and A. Vassilev, US National Institute of Standards and Technology (NIST). From Multisig and smart accounts.
Multisig: Short for multi-signature. On Ethereum, a smart contract account that needs a set number of valid signatures, out of a group of keys, before it acts. Source: ethereum.org developer docs. From Multisig and smart accounts.
Native token: A project's own token, such as UNI for Uniswap or OP for Optimism. Many DAO treasuries hold mostly their native token. Source: Blockchain Research Lab, Optimism Foundation, Optimism governance forum. From Treasury and runway.
Net asset value (NAV): A fund's total assets minus its total liabilities. Divide it by the number of shares to get the NAV per share. Source: Investor.gov, US Securities and Exchange Commission. From Real-world assets.
Net realisable value: The estimated selling price in the ordinary course of business, less the estimated costs to complete and sell. IAS 2 inventory is measured at the lower of cost and this amount. Source: IFRS Foundation (read 24 October 2026). From Crypto accounting basics.
NFT: A non-fungible token: a token that is individually unique, unlike ETH or USDC, where every unit is the same. Source: ethereum.org. From NFTs.
Node: A computer in a blockchain network that runs the network's software and connects to other nodes. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone), ethereum.org developer docs. From How a blockchain works.
Non-fungible token (NFT): A token that is one of a kind. In ERC-721, each has its own ID number, and its owner is tracked separately. Source: Ethereum Improvement Proposals (William Entriken, Dieter Shirley, Jacob Evans, Nastassia Sachs), ethereum.org developer docs. From Token standards.
Nonce: A number used only once. In proof of work, miners change it to get a new hash. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone). From How a blockchain works.
Nonce: A counter that numbers each transaction from an address, starting at 0. Source: Etherscan Information Center, ethereum.org developer docs. From Transactions, gas and fees.
Objects: The purposes set out in a foundation company's memorandum. They may, but need not, benefit other people. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Off-chain storage: Keeping an NFT's picture somewhere other than the blockchain, with the token pointing to it. Most NFT works are stored this way. Source: US Patent and Trademark Office and US Copyright Office. From NFTs.
Off-chain voting: Voting by signed messages outside the blockchain, with no gas fees. It doesn't move funds by itself. Source: Snapshot documentation (read 24 October 2026), ethereum.org (page last updated 26 June 2026; read 24 October 2026). From DAOs and governance.
On-ramp and off-ramp: An on-ramp swaps ordinary money for crypto. An off-ramp swaps crypto back into ordinary money. Source: Financial Action Task Force (FATF), updated June 2026, Financial Crimes Enforcement Network (FinCEN), US Department of the Treasury. From Banking and crypto.
Operating expenses: The everyday costs of running an organisation, such as payroll, legal, accounting and office costs. Source: Uniswap Foundation, Uniswap governance forum. From Treasury and runway.
Optimistic rollup: A rollup that assumes batches are valid unless someone proves fraud during a challenge period. Source: ethereum.org developer docs. From Layer 2s and bridges.
Oracle: A service that brings information from outside a blockchain, such as a price, to smart contracts. Source: ethereum.org developer docs. From Oracles.
Oracle manipulation: Pushing around the price an oracle reads, so a contract acts on a false value. Source: US Commodity Futures Trading Commission, press release 8647-23, ethereum.org developer docs. From Oracles.
Oracle problem: A blockchain can record data from the real world, but on its own it can't check that the data is true. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby and Scarfone). From Welcome to Web3.
Oracle problem: The difficulty of making sure outside data is correct, available and honest, when a contract has to trust whoever supplies it. Source: ethereum.org developer docs, ethereum.org developer docs. From Oracles.
Order book: The list of buy and sell orders waiting to be filled, grouped by price. Source: Uniswap Developers documentation (read 22 October 2026), Bank for International Settlements. From Exchanges, DEXs and AMMs.
Order book: An exchange's list of the buy orders (bids) and sell orders (asks) waiting to be matched. Source: Chainlink documentation, Kraken (Payward). From Liquidity, order books and slippage.
Other comprehensive income (OCI): Items of income and expense that IFRS Standards say are not recognised in profit or loss. Source: IFRS Foundation (read 24 October 2026). From Crypto accounting basics.
Over-collateralised: Secured by collateral worth more than the loan. DeFi loans are, because lenders can't check who borrowers are. Source: Aave Protocol Documentation, Bank for International Settlements (Sirio Aramonte, Sebastian Doerr, Wenqian Huang and Andreas Schrimpf). From Lending, borrowing and liquidations.
Over-collateralised: Backed by collateral worth more than the stablecoins issued, as a buffer against falling prices. Source: Board of Governors of the Federal Reserve System (Garth Baughman, Francesca Carapella, Jacob Gerszten and David Mills), Board of Governors of the Federal Reserve System (Cy Watsky and others). From Stablecoins.
Passphrase: An optional extra secret added to a recovery phrase. Every passphrase opens a valid wallet, but only the right one opens yours. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Self-custody.
Paymaster: Under ERC-4337, a helper contract that agrees to pay a transaction's fee instead of the user. Source: Ethereum Improvement Proposals (V. Buterin, Y. Weiss, D. Tirosh and others). From Multisig and smart accounts.
Payment stablecoin: The GENIUS Act's term for a digital asset used for payment, whose issuer must redeem it for a fixed amount of money. Source: US Congress, via the US Government Publishing Office. From Stablecoins.
Peg: The fixed value a stablecoin aims to keep, such as one US dollar per token. Source: Board of Governors of the Federal Reserve System (Garth Baughman, Francesca Carapella, Jacob Gerszten and David Mills), US Attorney's Office, Southern District of New York, US Department of Justice. From Stablecoins.
Permissioned token: A token that only approved, checked investors can hold or receive. Source: Ethereum Improvement Proposals (Lebrun, Malghem, Thizy, Falempin and Boudjemaa), status Final. From Real-world assets.
Permit signature: A signed message, under the ERC-2612 standard, that sets an allowance without a separate approval transaction. Source: Ethereum Improvement Proposals (Martin Lundfall), Revoke.cash, Learn pages (the maker of an approval-checking tool). From Security and common attacks.
Phishing: A form of social engineering: messages or fake websites that pose as someone trusted, to get your details or get you to open harmful links. Source: US Cybersecurity and Infrastructure Security Agency (CISA), blog (marked as archived content), US Cybersecurity and Infrastructure Security Agency (CISA), Secure Our World (marked as archived content). From Security and common attacks.
Pig butchering: A long investment scam in which the scammer builds trust over time, then steers the victim into a fake crypto platform. Source: US Treasury, Financial Crimes Enforcement Network (FinCEN), FBI Internet Crime Complaint Center, with the FBI Miami Field Office. From Security and common attacks.
Pre-seeding: A trick where a crook sets up a recovery phrase before a device reaches you, keeps a copy, and waits for you to add funds. Source: Ledger Academy (hardware-wallet maker's documentation). From Self-custody.
Price feed: An oracle that keeps a current price on-chain for contracts to read, such as ETH in US dollars. Source: ethereum.org developer docs, Chainlink documentation. From Oracles.
Price impact: How far a trade moves a pool's price. The bigger the trade compared with the pool, the bigger the move. Source: Uniswap Developers documentation (read 22 October 2026), 1inch Learn (read 22 October 2026). From Exchanges, DEXs and AMMs.
Price impact: How far your own trade moves the price, because it uses up the liquidity available. Source: Uniswap developer documentation, Chainlink documentation. From Liquidity, order books and slippage.
Principal market: The market with the greatest volume and level of activity for an asset that the holder can access. Fair value is measured using its price. Source: EY (Ernst & Young LLP), AccountingLink, PwC US National Office (Viewpoint). From Crypto accounting basics.
Priority fee (tip): An extra price per unit of gas, paid to the validator who includes your transaction. Source: ethereum.org developer docs, ethereum.org. From Transactions, gas and fees.
Private credit: Loans to private businesses from lenders that are not banks, such as private credit funds. Source: Board of Governors of the Federal Reserve System (Fang Cai and Sharjil Haque). From Real-world assets.
Private key: A huge random number that signs transactions. Anyone who has it controls the account, so it must stay secret. Source: Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub, ethereum.org (developer documentation), ethereum.org. From Wallets, keys and seed phrases.
Private key: A secret code that approves transactions from a wallet. It can't be changed, and losing it with no backup, such as a recovery phrase, means losing access. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov). From Self-custody.
Private token sale: Selling tokens directly to chosen buyers instead of on an open market, often with a lock-up. Source: Optimism Foundation, Optimism governance forum, Optimism Foundation, Optimism governance forum. From Treasury and runway.
Proof of reserves: A voluntary report that a firm's reserve assets covered customer balances at one point in time. Regulators' staff warn it is not an audit and may not cover debts. Source: US Securities and Exchange Commission, Office of Investor Education and Advocacy (staff views), Public Company Accounting Oversight Board, Office of the Investor Advocate (staff views); read via a Wayback Machine copy of 11 August 2026, as the live page showed a bot check. From Exchanges, DEXs and AMMs.
Proof of stake: A way to agree on new blocks: users lock up coins, and their chance of adding a block depends on their share of the stake. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone), ethereum.org developer docs. From How a blockchain works.
Proof of work: A way to agree on new blocks: the first computer to solve a hard guessing puzzle adds the next block. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone). From How a blockchain works.
Proof of work: Finding a number that makes a block's hash start with enough zeros. It takes many guesses to find, and one check to confirm. Source: Satoshi Nakamoto (the Bitcoin whitepaper). From Bitcoin.
Proof-of-stake: The way Ethereum has agreed on new blocks since 2022: validators lock up ETH that can be destroyed if they cheat. Source: ethereum.org developer docs, ethereum.org developer docs. From Ethereum and smart contracts.
Proposal: A set of actions, such as a payment from the treasury, that a DAO's Governor contract carries out if the vote passes. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Proposal threshold: The voting power an account needs before it can submit a proposal. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), Uniswap developer documentation (page says it was last updated in April 2026; read 24 October 2026). From DAOs and governance.
Provenance: An item's history, traced through who has owned it, held it and used it. Source: US Patent and Trademark Office and US Copyright Office. From NFTs.
Public good: Something people can't be barred from using, where one person's use doesn't take away from another's. Open-source code is often seen this way. Source: Gitcoin support knowledge base (read 22 October 2026). From Ecosystem grants.
Public key: A key worked out from the private key by one-way maths. It lets others check your signatures, but it can't be used to approve transactions. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov), Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Wallets, keys and seed phrases.
Public name tag: A name an explorer shows next to an address. It comes from the explorer, not from the chain. Source: Etherscan Information Center. From Reading the chain.
Pull oracle: An oracle whose signed prices wait off-chain until a user brings one on-chain in their own transaction. Source: Pyth Network blog, Chainlink documentation. From Oracles.
Pump and dump: Hyping an asset to push its price up, then selling into the rise. The price usually falls and later buyers lose. Source: Investor.gov, US Securities and Exchange Commission, US Commodity Futures Trading Commission (CFTC). From Security and common attacks.
Push oracle: An oracle whose operator keeps sending price updates to the chain, at set times or after big moves. Source: Pyth Network blog, Chainlink documentation. From Oracles.
Quadratic funding: A way to share a matching pool: take the square root of each gift, add them up and square the total, so many small gifts count for more than one big one. Source: Vitalik Buterin, Zoë Hitzig and E. Glen Weyl, arXiv:1809.06421, Gitcoin, mechanisms library. From Ecosystem grants.
Qualified person: Someone licensed or permitted under Cayman's Companies Management Act to provide company management services. A foundation company's secretary must be one. Source: Cayman Islands Government, Legislation Gazette, Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Quorum: The least voting power that must take part for a vote to count. DAOs differ on which votes count toward it. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), Arbitrum DAO governance forum, post by the forum account "Arbitrum", OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Real-world asset (RWA): An industry name for a token linked to an asset that exists outside the blockchain, such as a fund share, a loan or gold. Source: Financial Stability Board, Securitize press release, via PR Newswire. From Real-world assets.
Rebasing token: A token whose balance in your wallet changes as rewards, or losses, are added. Lido's stETH is one. Source: ethereum.org (read 24 October 2026; page last updated 17 August 2026), Lido documentation (read 24 October 2026). From Staking and yield.
Recoverable amount: Under IAS 36, the higher of an asset's fair value less costs to sell and its value in use. Source: IFRS Foundation (read 24 October 2026). From Crypto accounting basics.
Recovery phrase: Also called a seed phrase. The master key to a crypto wallet: anyone who has it can take everything in the wallet. Source: ethereum.org (the Ethereum community's website). From Welcome to Web3.
Recovery phrase (seed phrase): A list of 12 to 24 words that can rebuild every key in a wallet. Anyone who has it can drain the wallet. Source: Bitcoin Improvement Proposals (github.com/bitcoin/bips), ethereum.org. From Wallets, keys and seed phrases.
Recovery phrase (seed phrase): A list of words that can rebuild a wallet. Anyone who has it can take everything in the wallet. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov), ethereum.org. From Self-custody.
Redemption: Handing tokens or fund shares back to the issuer in exchange for cash or the underlying asset. Source: Ondo Finance documentation (read 22 October 2026), Financial Stability Board. From Real-world assets.
Redemption: Handing stablecoins back to the issuer in exchange for dollars or other assets. The issuer then destroys (burns) the tokens. Source: Board of Governors of the Federal Reserve System (Garth Baughman, Francesca Carapella, Jacob Gerszten and David Mills), New York State Department of Financial Services. From Stablecoins.
Reentrancy: A bug where a malicious contract calls back into a vulnerable contract before the first call has finished, for example to withdraw twice. Source: ethereum.org developer docs. From Security and common attacks.
Registered office: Where a company's official records are kept. For a foundation company, it is its secretary's business address. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Reputation risk: The risk that something a bank does could hurt how the public sees it, for reasons not clearly tied to its financial condition. Source: Federal Deposit Insurance Corporation (FDIC) Financial Institution Letter. From Banking and crypto.
Request for proposals (RFP): A funder's description of a specific problem, with a set scope and application window, inviting teams to propose a solution. Source: Ethereum Foundation blog, Ecosystem Support Program Team. From Ecosystem grants.
Reserve factor: The share of borrowers' interest that a protocol keeps for its treasury instead of passing it to lenders. Source: Aave Protocol Documentation, Aave Protocol Documentation. From Lending, borrowing and liquidations.
Reserves: The assets an issuer holds to back the stablecoins it has issued, such as cash and short-term Treasury bills. Source: US Congress, via the US Government Publishing Office, Circle Internet Group, with an examination report by its independent accountants. From Stablecoins.
Restaking: Using coins that are already staked to help secure other services too, for extra rewards and extra risks. Source: ethereum.org (read 24 October 2026; page last updated 15 May 2026). From Staking and yield.
Retainer: A deal where the project pays the market maker a fee, usually every month. Source: Presto Research (Min Jung). From Market makers: loan or retainer?.
Retroactive funding: Funding paid for work that has already shown impact, rather than for a proposal for future work. Source: Gitcoin, mechanisms library (read 22 October 2026), Optimism PBC blog on Medium, with Vitalik Buterin as guest author; read through the Internet Archive's Wayback Machine. From Ecosystem grants.
Revaluation model: An IAS 38 option to carry an intangible asset at fair value, open only where there is an active market. IAS 38 puts rises in other comprehensive income, unless they reverse an earlier fall charged to profit or loss; KPMG's summary shows rises above cost going there for crypto. Source: IFRS Foundation (read 24 October 2026), External Reporting Board (XRB), New Zealand Accounting Standards Board, KPMG Global Corporate Reporting Institute (IFRS). From Crypto accounting basics.
Revert: When a contract stops and undoes its changes. The gas used so far is still paid. Source: Ethereum Improvement Proposals (Alex Beregszaszi, Nikolai Mushegian), ethereum.org developer docs. From Transactions, gas and fees.
Risk-based approach: Understanding the money laundering risks you face and making your measures proportionate to them. Source: Financial Action Task Force (FATF), updated June 2026. From The rules: acts and regulators.
Rollup: A layer 2 that runs transactions off Ethereum, then posts their data back to Ethereum in batches. Source: ethereum.org developer docs, ethereum.org. From Layer 2s and bridges.
Royalty: A share of each resale paid to an NFT's creator. Under ERC-2981, paying it is voluntary for marketplaces. Source: Ethereum Improvement Proposals (Burks, Morgan, Malone and Seibel). From NFTs.
Rug pull: A project whose creator collects money from investors, then suddenly abandons it and keeps the money. Source: US Department of Justice, US Attorney's Office for the Southern District of New York (read through the Internet Archive copy of 11 December 2025, as justice.gov showed a bot check). From Security and common attacks.
Run: A self-reinforcing wave of redemptions and forced sales of reserve assets. Source: President's Working Group on Financial Markets, the Federal Deposit Insurance Corporation and the Office of the Comptroller of the Currency. From Stablecoins.
Runway: How long the money an organisation can spend will cover its operating expenses, usually counted in months. Source: ENS DAO governance forum (proposal posted by karpatkey, later KPK), ENS DAO governance documents (posted on the ENS forum on 8 May 2026; status: passed, in a Snapshot vote held from 24 to 29 June 2026). From Treasury and runway.
Safe module: An add-on contract that gives a Safe extra features, such as a daily spending allowance. It can skip the signature check, so a bad one can take over a Safe. Source: Safe documentation, Safe documentation. From Multisig and smart accounts.
Same-day and 30-day rules: UK rules that match a sale with the same token bought on the same day, or in the next 30 days, before the section 104 pool is used. Source: HM Revenue & Customs (HMRC), Cryptoassets Manual. From Crypto tax basics.
Sandwich attack: Trading just before and just after someone's large swap, to profit from the price move their swap causes. Source: ethereum.org developer docs, Uniswap Labs blog. From Liquidity, order books and slippage.
Satoshi (sat): The smallest unit of bitcoin. 100,000,000 sats make 1 BTC. Source: Bitcoin.org, Andreas M. Antonopoulos and David A. Harding (CC BY-SA 4.0), GitHub. From Bitcoin.
SDN List: OFAC's Specially Designated Nationals and Blocked Persons List. Since 2018 some entries include crypto addresses. Source: Office of Foreign Assets Control (OFAC), US Department of the Treasury. From The rules: acts and regulators.
Section 104 pool: In the UK, a single running total of all your tokens of one type, with one pooled cost, used to work out the cost of each sale. Source: HM Revenue & Customs (HMRC), Cryptoassets Manual, HM Revenue & Customs (GOV.UK guidance). From Crypto tax basics.
Self-custody: Holding your own private keys, so you alone control your crypto and are responsible for keeping it safe. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov). From Self-custody.
Self-hosted wallet: A crypto wallet not held by a service provider for its owner. The FATF calls it an unhosted wallet; EU law calls it a self-hosted address. Source: Financial Action Task Force (FATF), European Parliament and Council of the European Union, Official Journal L 150 (read on EUR-Lex). From Banking and crypto.
SEPA: The Single Euro Payments Area, which lets people make euro payments across 41 European countries as easily as at home. Source: European Central Bank, read 22 October 2026. From Banking and crypto.
Separation of duties: The principle that no one person should have enough power to misuse a system alone. For example, the person who approves a payment should not also prepare it. Source: US National Institute of Standards and Technology (NIST), Computer Security Resource Center (read 24 October 2026). From Treasury and runway.
Separation of duty: The security principle that no one person should have enough power to misuse a system on their own. Source: US National Institute of Standards and Technology (NIST), Computer Security Resource Center. From Multisig and smart accounts.
Sequencer: An operator that orders a rollup's transactions and posts its batches. Some rollups have a single one. Source: ethereum.org developer docs, ethereum.org developer docs. From Layer 2s and bridges.
SHA-256: A hash function from a US standard, FIPS 180-4. Its digest is 256 bits long. Bitcoin uses it. Source: US National Institute of Standards and Technology (Yaga, Mell, Roby, Scarfone), US National Institute of Standards and Technology. From How a blockchain works.
Sidechain: A separate blockchain with its own rules and validators, linked to Ethereum by a two-way bridge. Source: ethereum.org developer docs. From Layer 2s and bridges.
SIM swap: Getting someone's phone number moved to a SIM card a criminal controls, so their calls and texts go to the criminal. Source: FBI Internet Crime Complaint Center. From Self-custody.
Slashing: The penalty for provable cheating by a validator: part of its stake is destroyed and it is forced out of the network. Source: ethereum.org developer documentation (read 24 October 2026; page last updated 28 September 2026), ethereum.org (read 24 October 2026). From Staking and yield.
Slippage: The gap between the price you were quoted and the price your trade actually got. Source: Uniswap Labs blog, FINRA (Financial Industry Regulatory Authority). From Liquidity, order books and slippage.
Slippage tolerance: The most the price may move against you before a DEX swap is cancelled instead of filled. Source: Uniswap Labs blog, Uniswap developer documentation. From Liquidity, order books and slippage.
Smart account: An account controlled by smart contract code rather than by one private key. Its code decides who can move funds, and how. Source: Safe documentation (Safe Smart Account overview). From Multisig and smart accounts.
Smart contract: A program that runs on Ethereum: code and data stored at its own address. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Smart contract exploit: Using a flaw in a smart contract to take funds in a way its builders did not intend. Source: FBI Internet Crime Complaint Center, ethereum.org developer docs. From Security and common attacks.
Snapshot of voting power: A record of balances at a set point, so that tokens bought, borrowed or moved later can't vote on that proposal. Source: Snapshot documentation (read 24 October 2026), OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Social engineering: Using human contact, such as pretending to be someone trusted, to get information or access. Source: US Cybersecurity and Infrastructure Security Agency (CISA), blog (marked as archived content). From Security and common attacks.
Solidity: A high-level language for writing smart contracts that run on the EVM. Source: Solidity documentation, The Solidity Authors. From Ethereum and smart contracts.
Special purpose vehicle (SPV): A separate legal entity, set up by a sponsoring firm, that usually only holds and finances specific assets. Source: The Joint Forum (Basel Committee, IOSCO and IAIS), Bank for International Settlements. From Real-world assets.
Specific identification: A cost method that matches the actual cost of the exact units sold, which only works if those units can be identified. Source: US Internal Revenue Service (IRS), EY (Ernst & Young LLP), AccountingLink. From Crypto accounting basics.
Split backup: A backup split into shares, where a set number of shares rebuild the wallet and fewer reveal nothing. SLIP-39 is one standard for it. Source: SatoshiLabs Improvement Proposals (github.com/satoshilabs/slips). From Self-custody.
Spoofing: Placing buy or sell orders you plan to cancel before anyone can trade with them. Source: US Commodity Futures Trading Commission. From Market makers: loan or retainer?.
Spread: The gap between the bid and the ask. Source: Investor.gov, US Securities and Exchange Commission. From Market makers: loan or retainer?.
Stablecoin: A crypto-asset that aims to keep a stable value against a set asset, such as the US dollar, or a basket of assets. Source: Financial Stability Board, President's Working Group on Financial Markets, the Federal Deposit Insurance Corporation and the Office of the Comptroller of the Currency. From Stablecoins.
Stablecoin floor: A rule that a set amount must always be kept in stablecoins. ENS DAO's 2026 policy sets it at three years of operating expenses. Source: ENS DAO governance documents (posted on the ENS forum on 8 May 2026; status: passed, in a Snapshot vote held from 24 to 29 June 2026). From Treasury and runway.
Staking: Locking up a proof-of-stake network's coins so that they can be used to help run the network, in return for rewards. Source: ethereum.org (read 24 October 2026), US Securities and Exchange Commission, Division of Corporation Finance. From Staking and yield.
Staking as a service: Delegated staking: you deposit your own 32 ETH, and a third-party operator runs the validator for a fee. Source: ethereum.org (read 24 October 2026; page last updated 17 August 2026). From Staking and yield.
Stop order: An order that turns into a market order once the price reaches a set stop price. Source: Investor.gov, US Securities and Exchange Commission, Office of Investor Education and Assistance. From Liquidity, order books and slippage.
Store of value: Something expected to keep its value in a fairly predictable way over time. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
Stress test: Checking how a plan or balance sheet would hold up under a hypothetical bad scenario, such as a deep recession or a big price fall. Source: Board of Governors of the Federal Reserve System (read 24 October 2026). From Treasury and runway.
Strict liability: A legal standard under which a person can be held liable for a violation even without knowing, or having reason to know, about it. Source: Office of Foreign Assets Control (OFAC), US Department of the Treasury. From The rules: acts and regulators.
Supervisor: A person, other than a member, who has an unconditional right under the constitution to attend and vote at general meetings. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Sybil attack: One person posing as many. In quadratic funding it is used to win a bigger share of the matching pool. Source: Vitalik Buterin, Zoë Hitzig and E. Glen Weyl, arXiv:1809.06421v2, Gitcoin research, by Kevin Owocki. From Ecosystem grants.
Systemic risk exception: The special decision in March 2023 that let the FDIC protect all depositors of Silicon Valley Bank and Signature Bank, insured or not. Source: US Treasury Secretary Janet L. Yellen, Federal Reserve Board Chair Jerome H. Powell and FDIC Chairman Martin J. Gruenberg (FDIC press release), Federal Deposit Insurance Corporation (FDIC) press release. From Banking and crypto.
Taker: A trader whose order matches straight away against orders already on the book, removing liquidity. Source: Kraken (Payward). From Liquidity, order books and slippage.
Temperature check: An early, non-binding poll, often on Snapshot, to see whether a proposal has support. Source: Uniswap developer documentation (page says it was last updated in April 2026; read 24 October 2026), Arbitrum DAO governance documentation (read 24 October 2026). From DAOs and governance.
The Merge: The upgrade of 15 September 2022 that joined Ethereum with the Beacon Chain and replaced mining with staking. Source: ethereum.org roadmap. From Ethereum and smart contracts.
Third-party custody: A company, such as an exchange or custody firm, holds the private keys for you. Source: US Securities and Exchange Commission, Office of Investor Education and Assistance (Investor.gov). From Self-custody.
Threshold: The least number of owners who must confirm a transaction before a multisig such as a Safe will carry it out. Source: Safe documentation. From Multisig and smart accounts.
Threshold signature: One ordinary-looking signature made by enough holders of a shared key. It is checked against a single public key. Source: Bitcoin Optech (topics). From Multisig and smart accounts.
Timelock: A forced delay before an approved change to a system takes effect, giving users time to leave if they disagree. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Timelock: A contract that makes a passed proposal wait a set time before it runs, so users can react or leave. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), Compound documentation (v2, read 24 October 2026). From DAOs and governance.
Token account: On Solana, the account that holds one owner's balance of one token. A wallet needs one for each token it holds. Source: Solana documentation, Solana Foundation. From Token standards.
Token allocation: How a project splits its supply between groups such as the team, investors, a treasury and the community. Source: CoinMarketCap Academy. From Tokenomics, vesting and unlocks.
Token approval: Permission you give a smart contract to spend your tokens on your behalf. Source: Revoke.cash, Learn pages (the maker of an approval-checking tool), Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin). From Security and common attacks.
Token approval: Permission you give an app to spend your tokens. Explorers can list approvals and help you revoke them. Source: Etherscan Information Center, ethereum.org guide. From Reading the chain.
Token approval: Permission you give a smart contract to move up to a set amount of one of your tokens, or an unlimited amount. Disconnecting your wallet does not cancel it. Source: ethereum.org (read 22 October 2026), Uniswap Developers documentation (read 22 October 2026). From Exchanges, DEXs and AMMs.
Token dilution: When new tokens are created, each existing token becomes a smaller share of the total supply. Source: Anza (Agave validator client documentation for Solana) (read 24 October 2026). From Staking and yield.
Token extensions (Token 2022): Solana's newer token program, which adds optional features such as transfer fees or non-transferable tokens. Source: Solana documentation, Solana Foundation, Solana documentation, Solana Foundation. From Token standards.
Token generation event (TGE): The moment a project first creates and issues its token. Arbitrum counted its first team and investor unlocks from it. Source: Chainlink Education (chain.link); Chainlink is a company with its own commercial interests (read 24 October 2026), Arbitrum DAO governance docs, Arbitrum Foundation (read 22 October 2026). From Tokenomics, vesting and unlocks.
Token ID: The number that identifies one NFT inside its contract. With the contract address, it picks out exactly one NFT. Source: Ethereum Improvement Proposals (Entriken, Shirley, Evans and Sachs). From NFTs.
Token loan agreement: A deal where a market maker borrows a project's tokens for a set time, usually paid with call options. Source: Presto Research (Min Jung). From Market makers: loan or retainer?.
Token standard: A shared set of rules for how a token contract behaves, so wallets, exchanges and apps can work with any token that follows it. Source: ethereum.org developer docs. From Token standards.
Tokenisation: Creating and recording a digital version of a traditional asset on a programmable platform, such as a blockchain. Source: Bank for International Settlements and Committee on Payments and Market Infrastructures, report to the G20. From Real-world assets.
Tokenomics: How a token's supply and demand are designed: how many exist, how many more will be made, who holds them and when they unlock. Source: CoinMarketCap Academy. From Tokenomics, vesting and unlocks.
tokenURI: An ERC-721 function that gives the address of a token's metadata. ERC-721 lets this address change. Source: Ethereum Improvement Proposals (Entriken, Shirley, Evans and Sachs). From NFTs.
Total supply: The tokens that exist right now, including locked ones, minus any burned. Source: CoinMarketCap Academy (read 22 October 2026), CoinMarketCap Academy. From Tokenomics, vesting and unlocks.
Transaction: A signed instruction from an account, such as sending ETH to an address. Source: ethereum.org developer docs. From Transactions, gas and fees.
Transaction hash: A transaction's unique ID, a long string of letters and numbers. The FBI asks scam victims to report it. Source: FBI Internet Crime Complaint Center. From Security and common attacks.
Transaction hash: A unique code for one transaction, used to look it up. Also called a transaction ID or txid. Source: Etherscan Information Center, Bitcoin Developer Documentation (developer.bitcoin.org). From Reading the chain.
Transfer agent: The firm that keeps the record of who owns a security, records changes of ownership and pays out dividends. Source: US Securities and Exchange Commission, Division of Trading and Markets. From Real-world assets.
Transfer event: The log an ERC-20 token contract must write whenever tokens move. It holds from, to and value. Source: Ethereum Improvement Proposals (Fabian Vogelsteller, Vitalik Buterin). From Reading the chain.
Travel Rule: The FATF's wire transfer rule applied to crypto: details about the sender and receiver must pass between the providers handling a transfer. Source: Financial Action Task Force (FATF), Financial Action Task Force (FATF). From Banking and crypto.
Travel Rule: The rule that a sending VASP must collect sender and receiver details for a crypto transfer and pass them to the receiving VASP. Source: Financial Action Task Force (FATF), updated June 2026. From The rules: acts and regulators.
Treasury: The money an organisation holds to pay its way: cash at banks, stablecoins, tokens and other assets. Source: Filed with the US Securities and Exchange Commission, Uniswap Foundation, Uniswap governance forum. From Treasury and runway.
TWAP: Time-weighted average price: an average of a price over a period, so a short spike counts for little. Source: Uniswap developer docs, ethereum.org developer docs. From Oracles.
TWAP order: An order that splits a large trade into smaller pieces traded at set intervals, to reduce price impact. Source: CoW Protocol documentation. From Liquidity, order books and slippage.
TWAP order: An order that splits a large trade into smaller limit orders spread over time. TWAP stands for time-weighted average price. Source: CoW Protocol documentation (read 24 October 2026). From Treasury and runway.
Two-sided quote: Showing a buy price and a sell price at the same time. Source: US Securities and Exchange Commission, press release 2010-216, Norwegian Block Exchange (NBX). From Market makers: loan or retainer?.
Typed data (EIP-712): A standard way to sign structured messages, so a wallet can show what each field means before you sign. Source: Ethereum Improvement Proposals (eips.ethereum.org). From Wallets, keys and seed phrases.
Uninsured deposits: Money in a bank above the deposit insurance limit. Its owner may not get it all back if the bank fails. Source: Federal Deposit Insurance Corporation (FDIC), read 22 October 2026, New York State Department of Financial Services (DFS). From Banking and crypto.
Unit of account: The thing prices are written in, for example on menus, contracts or price labels. Source: Bank of England, Quarterly Bulletin 2014 Q1 (McLeay, Radia and Thomas). From Welcome to Web3.
Unlimited approval: An approval with no practical limit, so the spender can take all of that token in the wallet, with no expiry date. Source: ethereum.org guides, ethereum.org. From Security and common attacks.
Unlock: The moment locked or vesting tokens become free to move, adding to circulating supply. Source: CoinMarketCap Academy, Arbitrum DAO governance docs, Arbitrum Foundation (read 22 October 2026). From Tokenomics, vesting and unlocks.
Utilisation rate: The share of a pool that is lent out: total borrowed divided by total supplied. Source: Compound III documentation, Aave Protocol Documentation. From Lending, borrowing and liquidations.
UTXO: Unspent transaction output: an amount of bitcoin waiting to be spent. A wallet's balance is the total of its UTXOs. Source: Bitcoin Developer Documentation (developer.bitcoin.org). From Bitcoin.
UTXO: An unspent transaction output: an amount of bitcoin waiting to be spent by a later input. Source: Bitcoin Developer Documentation (developer.bitcoin.org). From Reading the chain.
Validator: On Ethereum, a user who has deposited at least 32 ETH and runs software to check and propose blocks. Source: ethereum.org developer docs, ethereum.org roadmap. From How a blockchain works.
Validator: A participant who has staked ETH to check new blocks and sometimes propose them. Source: ethereum.org developer docs. From Ethereum and smart contracts.
Validity proof: A cryptographic proof that a batch's changes really come from running its transactions. Source: ethereum.org developer docs. From Layer 2s and bridges.
Variable rate: An interest rate that keeps changing as the pool's utilisation changes. Source: Aave, aave/risk-v3 repository on GitHub. From Lending, borrowing and liquidations.
VASP (virtual asset service provider): A person or company that, as a business and for others, exchanges, transfers or keeps virtual assets, or provides financial services for a token sale. Source: Financial Action Task Force (FATF), updated June 2026. From The rules: acts and regulators.
Vault shares: The tokens an ERC-4626 vault gives you for a deposit. Each share is a claim on part of what the vault holds. Source: Ethereum Improvement Proposals (Joey Santoro, t11s, Jet Jadeja, Alberto Cuesta Cañada, Señor Doggo). From Token standards.
Verified contract: A contract whose source code an explorer has checked compiles to the code on the chain. It does not mean the contract is safe. Source: ethereum.org developer docs, Etherscan Information Center. From Reading the chain.
Vesting: Releasing tokens to their owner bit by bit, according to a schedule. Source: OpenZeppelin Contracts 5.x documentation (read 22 October 2026). From Tokenomics, vesting and unlocks.
Vesting: Releasing tokens bit by bit over time. With a cliff, nothing is released before a set date. Source: OpenZeppelin Contracts 5.x documentation (read 22 October 2026). From Ecosystem grants.
Virtual asset: FATF's term for a digital representation of value that can be digitally traded or transferred and used for payment or investment. It does not include digital versions of fiat money or securities. Source: Financial Action Task Force (FATF), updated June 2026. From The rules: acts and regulators.
Virtual asset service: Under Cayman's VASP Act, issuing virtual assets, or exchanging, transferring or keeping them safe for others as a business. Source: Cayman Islands Government, Legislation Gazette. From Cayman foundation companies.
Virtual asset service provider (VASP): The FATF's name for a business that, for customers, exchanges, transfers or keeps virtual assets, among other services. Source: Financial Action Task Force (FATF), updated June 2026. From Banking and crypto.
Voting delay: The time between a proposal being submitted and voting starting. Voting power is fixed when it ends. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Voting period: How long a proposal stays open for votes. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), OpenZeppelin Contracts 5.x documentation (read 24 October 2026). From DAOs and governance.
Voting threshold: The share of votes in favour that a proposal needs to pass, such as a simple majority or two-thirds. Source: OpenZeppelin Contracts 5.x documentation (read 24 October 2026), Immunefi, a security firm (article by one of its smart contract triagers). From DAOs and governance.
Wallet: An app or device that holds your keys and lets you see balances, send and receive crypto, and sign in to apps. The coins themselves stay on the blockchain. Source: ethereum.org, Andreas M. Antonopoulos, Gavin Wood and co-authors (CC BY-NC-ND 4.0 for its first 12 months, then CC BY-SA 4.0), GitHub. From Wallets, keys and seed phrases.
Wallet drainer: A malicious smart contract or program that moves crypto and NFTs out of a victim's wallet to criminals once the victim connects or approves it. Source: FBI Internet Crime Complaint Center, FBI Internet Crime Complaint Center. From Security and common attacks.
Wash trading: Trading with yourself, or with a partner, to make it look like real buying and selling is happening. Source: US Commodity Futures Trading Commission, US Department of Justice / FBI. From Market makers: loan or retainer?.
Watch-only wallet: A wallet that holds addresses or public keys but no private keys, so it can watch balances and payments but can't spend. Source: Andreas M. Antonopoulos, Gavin Wood and co-authors (CC BY-NC-ND 4.0 for its first 12 months, then CC BY-SA 4.0), GitHub, Bitcoin Improvement Proposals (github.com/bitcoin/bips). From Wallets, keys and seed phrases.
Web3: A catch-all term for a vision of an internet where users own things, built on blockchains and tokens. Source: ethereum.org (the Ethereum community's website). From Welcome to Web3.
Wei: The smallest unit of ETH. There are 1,000,000,000,000,000,000 wei (a 1 followed by 18 zeros) in 1 ETH. Source: ethereum.org developer docs, ethereum.org developer docs. From Ethereum and smart contracts.
Wei: The smallest unit of ETH. 1 gwei is 1,000,000,000 wei. Source: ethereum.org developer docs. From Transactions, gas and fees.
Wishlist: ESP's list of broad gaps in the ecosystem, inviting builders to propose their own ideas to fill them. Source: Ethereum Foundation blog, Ecosystem Support Program Team. From Ecosystem grants.
Withdrawal address: The address a validator's staked ETH and rewards are sent to. On Ethereum it can be set only once. Source: ethereum.org (read 24 October 2026; page last updated 17 August 2026). From Staking and yield.
Wrapped token: A token on one chain that stands for an asset held on another, such as WBTC for bitcoin. Source: ethereum.org, CNN Business. From Layer 2s and bridges.
Wrapping a DAO: Forming a legal entity, such as a foundation company, to act as a DAO's formal legal representative or operating body. Source: Walkers (law firm briefing). From Cayman foundation companies.
Yield: What an investment earns over a year, shown as a percentage of the amount put in. Source: Electronic Code of Federal Regulations, US Government (read 24 October 2026, through the eCFR's own content service). From Staking and yield.
Zero-value transfer: A token transfer of zero tokens that an attacker can make appear to come from your address. Source: Revoke.cash, Learn pages (the maker of an approval-checking tool), Taro Tsuchiya, Jin-Dong Dong, Kyle Soska and Nicolas Christin (Carnegie Mellon University and independent), Proceedings of the 34th USENIX Security Symposium. From Security and common attacks.
ZK rollup: A zero-knowledge rollup: it posts a cryptographic proof that each batch is correct. Source: ethereum.org developer docs. From Layer 2s and bridges.