Crypto glossary
102 crypto words explained in a sentence or two, each linked to related terms and a fuller guide.
%
51% attack
When one group controls more than half of a network's mining power or stake and can rewrite recent transactions.
Related: Proof of work, Double spend · Read more →
A
Address
A string of letters and numbers where crypto can be sent, like an account number. It's made from your public key and is safe to share.
Related: Public key, Private key, Wallet · Read more →
Airdrop
Free tokens sent to many wallets, often to promote a project. Real ones exist, but fake 'claim your airdrop' sites are a common way to steal crypto.
Related: Wallet drainer, Phishing · Read more →
AML / KYC
Anti-money-laundering and know-your-customer rules. They're why regulated exchanges ask for your ID.
Related: Exchange · Read more →
Approval
Permission you sign in your wallet that lets a smart contract move some of your tokens. Malicious approvals can empty a wallet, so only approve sites you trust.
Related: Smart contract, Wallet drainer · Read more →
ASIC
A computer chip built for one job. Bitcoin mining is done almost entirely with ASIC machines.
Related: Mining, Proof of work · Read more →
B
Base fee
On Ethereum, the minimum price per unit of gas for the next block, set by the network and burned.
Related: Gas, Gwei, Burn · Read more →
Bitcoin (BTC)
The first cryptocurrency, launched in 2009, with a maximum supply of 21 million coins.
Related: Satoshi, Halving, Proof of work · Read more →
Bitcoin ATM
A kiosk that turns cash into bitcoin. Legitimate, but heavily used in scams; no real bank or agency will ever tell you to use one.
Related: Scam · Read more →
Block
A batch of transactions added to a blockchain together.
Related: Blockchain, Hash, Confirmation · Read more →
Block explorer
A website that lets anyone look up transactions, addresses and blocks on a blockchain.
Related: Address · Read more →
Block reward
New coins paid to the miner or validator who adds a block. On Bitcoin it's 3.125 BTC per block since April 2024.
Related: Halving, Mining · Read more →
Blockchain
A shared record of transactions, grouped into blocks that each contain the fingerprint (hash) of the block before.
Related: Block, Hash, Node · Read more →
Bridge
A service that moves tokens from one blockchain network to another. Bridges have been frequent targets of large hacks.
Related: Layer 2 · Read more →
C
Capital gain
Profit from selling an asset for more than its cost basis. In the US, crypto gains are taxed as capital gains.
Related: Cost basis · Read more →
CBDC
Central bank digital currency: digital money issued by a country's central bank. It isn't a decentralized cryptocurrency.
Related: Stablecoin · Read more →
Coin vs. token
A coin is native to its own blockchain (BTC, ETH); a token is built on top of one (USDC on Ethereum).
Related: Token · Read more →
Cold wallet
A wallet whose private keys are kept offline, such as a hardware wallet.
Related: Hardware wallet, Hot wallet · Read more →
Confirmation
A count of how many blocks have been added since your transaction was included. More confirmations mean it's more firmly settled.
Related: Block, Mempool · Read more →
Consensus mechanism
The rules a network uses to agree on which transactions and blocks are valid.
Related: Proof of work, Proof of stake · Read more →
Cost basis
What you paid for an asset, including fees. Used to work out your gain or loss for taxes.
Related: Capital gain · Read more →
Custodial
When a company holds your crypto's private keys for you, as most exchanges do.
Related: Self-custody, Exchange · Read more →
D
DAO
Decentralized autonomous organization: a group that makes decisions by token-holder votes enforced by smart contracts.
Related: Governance token, Smart contract
dApp
A decentralized application: an app whose core logic runs as smart contracts on a blockchain.
Related: Smart contract, DeFi · Read more →
DCA (dollar-cost averaging)
Buying a fixed dollar amount on a regular schedule regardless of price.
Related: Cost basis · Read more →
DeFi
Decentralized finance: lending, borrowing and trading through smart contracts rather than banks or companies.
Related: DEX, Smart contract, Stablecoin · Read more →
Depeg
When a stablecoin's price moves away from its target, such as $1.
Related: Stablecoin · Read more →
DEX
Decentralized exchange: smart contracts that let you swap tokens directly from your wallet.
Related: Exchange, DeFi · Read more →
Difficulty
How hard it is to find a valid block in proof of work. Bitcoin adjusts it every 2,016 blocks to keep blocks about 10 minutes apart.
Related: Mining, Proof of work · Read more →
Double spend
Spending the same digital money twice. Blockchains exist largely to prevent it without a central referee.
Related: Consensus mechanism, 51% attack · Read more →
E
ERC-20
The standard format for ordinary tokens on Ethereum, such as USDC.
Related: Token, ERC-721 · Read more →
ERC-721
The standard format for NFTs on Ethereum: each token is unique.
Related: NFT, ERC-20 · Read more →
ETF (spot crypto ETF)
A fund traded on a stock exchange that holds crypto such as bitcoin, letting you invest through a normal brokerage without holding the coins yourself.
Related: Exchange · Read more →
Ether (ETH)
The native coin of the Ethereum network, used to pay gas fees and for staking.
Related: Ethereum, Gwei, Wei · Read more →
Ethereum
A blockchain that runs smart contracts, home to most tokens, DeFi and NFTs. Secured by proof of stake since 2022.
Related: Ether (ETH), Smart contract, Gas · Read more →
Exchange
A platform for buying, selling and swapping crypto. Centralized exchanges are companies; decentralized ones are smart contracts.
Related: DEX, Custodial · Read more →
F
Finality
The point at which a transaction can't realistically be reversed. Showing up fast isn't the same as being final.
Related: Confirmation, Block · Read more →
FOMO
Fear of missing out: the urge to buy because prices are rising and others seem to be getting rich. Scammers exploit it.
Related: Scam
Fork
A change to a blockchain's rules. A hard fork can split one network into two separate coins.
Related: Node
G
Gas
The unit measuring the computing work an Ethereum transaction needs. A plain ETH transfer uses 21,000 gas.
Related: Gwei, Base fee · Read more →
Genesis block
The first block of a blockchain. Bitcoin's was mined on January 3, 2009.
Related: Block, Satoshi Nakamoto · Read more →
Gwei
One billionth of an ETH (0.000000001 ETH). Gas prices are quoted in gwei.
Related: Gas, Wei, Ether (ETH) · Read more →
H
Halving
The roughly four-yearly event that cuts Bitcoin's block reward in half. The last was in April 2024 (to 3.125 BTC); the next is expected around 2028.
Related: Block reward, Bitcoin (BTC) · Read more →
Hardware wallet
A small device that keeps private keys offline and signs transactions inside the device.
Related: Cold wallet, Seed phrase · Read more →
Hash
A fixed-length fingerprint of data. Change the data slightly and the hash changes completely.
Related: Block, Proof of work · Read more →
Hash rate
The total guessing power of a proof-of-work network, a measure of how much work protects it.
Related: Mining, Difficulty · Read more →
HODL
Crypto slang for holding long-term rather than selling, from a misspelled 2013 forum post.
Hot wallet
A wallet app connected to the internet, on a phone, computer or browser.
Related: Cold wallet, Wallet · Read more →
L
Layer 2
A network built on top of a layer 1 that processes transactions more cheaply and posts the results back to it, such as Arbitrum or Base.
Related: Rollup, Bridge, Layer 1 · Read more →
Leverage
Borrowing to make a bigger bet. It multiplies gains and losses, and can wipe out your money quickly in crypto's price swings.
Related: Liquidation
Liquidation
When a lender or exchange automatically sells your collateral because a leveraged position or loan has lost too much value.
Related: Leverage
M
Market cap
Price × number of coins in circulation. A rough measure of a cryptocurrency's total value.
Related: Supply
Meme coin
A token based on a joke or internet meme, usually with no use beyond speculation. Extremely volatile; most become worthless.
Related: Token, Rug pull · Read more →
Mempool
The waiting room of unconfirmed transactions before they go into a block.
Related: Confirmation, Network fee · Read more →
Mining
Using computers to add blocks to a proof-of-work blockchain and earn new coins and fees.
Related: Proof of work, ASIC, Block reward · Read more →
N
Network fee
The fee paid to miners or validators to process a transaction. Called gas on Ethereum.
Related: Gas, Mempool · Read more →
NFT
Non-fungible token: a unique token recording ownership of a specific item, often digital art or a collectible.
Related: ERC-721, Token · Read more →
Node
A computer running a blockchain's software, keeping a copy of the ledger and checking the rules.
Related: Blockchain, Validator · Read more →
Nonce
In mining, the number miners keep changing to search for a valid block hash.
Related: Proof of work, Hash · Read more →
P
Phishing
Fake messages, sites or apps that trick you into revealing logins, codes or your seed phrase.
Related: Seed phrase, Scam · Read more →
Pig butchering
A long-con investment scam: a stranger builds a friendship or romance online, then guides you onto a fake crypto platform.
Related: Scam · Read more →
Private key
The secret number that controls your crypto and signs transactions. Never share it.
Related: Public key, Seed phrase · Read more →
Proof of stake
A consensus method where validators lock up coins as a deposit and are chosen to add blocks. Used by Ethereum.
Related: Staking, Validator, Slashing · Read more →
Proof of work
A consensus method where miners compete with computing power to add blocks. Used by Bitcoin.
Related: Mining, Hash, Difficulty · Read more →
Pseudonymous
Using an identifier, like a crypto address, instead of your real name. Most blockchains are pseudonymous, not anonymous.
Related: Address, Block explorer · Read more →
Public key
A key calculated from your private key, used to check your signatures. Your address is made from it.
Related: Private key, Address · Read more →
R
Rollup
A kind of layer 2 that bundles many transactions into one batch posted to the main chain.
Related: Layer 2 · Read more →
Rug pull
When a project's creators take investors' money and abandon it, often by dumping their tokens.
Related: Meme coin, Scam · Read more →
S
Satoshi
The smallest unit of bitcoin: 0.00000001 BTC. 100 million satoshis make one bitcoin.
Related: Bitcoin (BTC) · Read more →
Satoshi Nakamoto
The pseudonymous creator of Bitcoin, whose real identity is unknown.
Related: Bitcoin (BTC), Genesis block · Read more →
Scam
A trick to get you to send money or reveal secrets. Crypto scams cost Americans more than $11 billion in reported losses in 2025.
Related: Phishing, Pig butchering, Rug pull · Read more →
Seed phrase
12 or 24 words that can restore every key in a wallet. Also called a recovery phrase. Whoever has it controls your crypto.
Related: Private key, Hardware wallet · Read more →
Self-custody
Holding your own private keys, so no company stands between you and your crypto.
Related: Custodial, Wallet · Read more →
Slashing
A proof-of-stake penalty that destroys part of a validator's stake for breaking the rules.
Related: Proof of stake, Validator · Read more →
Slippage
The difference between the price you expected and the price you actually got, usually bigger for large orders and thinly traded coins.
Related: Liquidity, Spread · Read more →
Smart contract
A program stored on a blockchain that runs exactly as written when used.
Related: Ethereum, DeFi, Approval · Read more →
Spread
The gap between the price you buy at and the market price (or between buy and sell prices). A hidden cost.
Related: Liquidity · Read more →
Stablecoin
A cryptocurrency designed to keep a steady value, usually $1, such as USDC or USDT.
Related: Depeg, Fiat · Read more →
Staking
Locking up coins to help secure a proof-of-stake network in return for rewards.
Related: Proof of stake, Validator · Read more →
Supply
How many coins exist (circulating supply) or ever will (maximum supply). Bitcoin's maximum is 21 million.
Related: Market cap, Halving
T
Token
A crypto asset built on another blockchain using a smart contract, rather than having its own blockchain.
Related: Coin vs. token, ERC-20 · Read more →
Transaction ID (TXID)
The unique code for a transaction, used to look it up on a block explorer.
Related: Block explorer · Read more →
Two-factor authentication (2FA)
A second login step. Use an authenticator app or security key rather than text messages for crypto accounts.
Related: Phishing · Read more →
U
USDC
A US dollar stablecoin issued by Circle, backed by cash and short-term US Treasuries.
Related: Stablecoin · Read more →
USDT (Tether)
The largest US dollar stablecoin by value, issued by Tether.
Related: Stablecoin, USDC · Read more →
V
Validator
A participant in a proof-of-stake network that stakes coins and proposes and checks blocks.
Related: Proof of stake, Staking · Read more →
Volatility
How much and how fast a price moves. Crypto is far more volatile than most stocks.
Related: Bear market, Bull market
W
Wallet
An app or device that stores your private keys and lets you send and receive crypto.
Related: Hot wallet, Cold wallet, Seed phrase · Read more →
Wallet drainer
Malicious code, usually on a fake website, that tricks you into signing approvals that empty your wallet.
Related: Approval, Phishing · Read more →
Whale
Someone who holds a very large amount of a cryptocurrency, enough to move its price.
Whitepaper
A document describing how a crypto project is supposed to work. Bitcoin's was published in 2008.
Related: Satoshi Nakamoto · Read more →
Y
Yield
A return paid on crypto for staking, lending or providing liquidity. Always ask where it comes from: high yields usually mean high risk.
Related: Staking, DeFi · Read more →