The ZeroToBlock blockchain glossary is a free, technically accurate dictionary of 136 terms across 7 categories — from Bitcoin, Proof of Work and mining to Ethereum, smart contracts, DeFi, NFTs and zero-knowledge proofs. Each definition is written by educators, cross-linked to related concepts and backed by our interactive blockchain courses.
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Start here if you're new to blockchain or crypto:
- Bitcoin — The first decentralised digital currency, launched in 2009.
- Blockchain — A chained, append-only ledger of blocks.
- Proof of Work — A consensus mechanism that requires computational work to add blocks.
- Smart Contract — Code on a blockchain that automatically enforces its rules.
- Ethereum — A programmable blockchain that supports smart contracts.
- Wallet — Software or hardware that manages your private keys.
- Private Key — The secret number that authorises spending from an address.
- Seed Phrase — A human-readable backup of a wallet's private keys.
- Mining — Producing new blocks by performing Proof of Work.
- Halving — The scheduled 50% cut in Bitcoin's block subsidy.
- DeFi (Decentralized Finance) — Financial services built from smart contracts.
- NFT (Non-Fungible Token) — A unique, non-interchangeable token on a blockchain.
- Stablecoin — A cryptocurrency designed to track a stable reference value.
- Gas Fee — What you pay to execute a transaction on Ethereum.
- Layer 2 (L2) — A scaling network that settles to a Layer 1.
- Zero-Knowledge Proof — Proving you know something without revealing what it is.
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136 terms
Bitcoin
Address (Bitcoin / Crypto Address)
A public destination for receiving cryptocurrency.
Block Header
The metadata at the top of each block.
Block Reward
New coins paid to the miner of a block.
Difficulty
A parameter that controls how hard it is to mine a block.
Double Spend
Attempting to spend the same coin twice.
Halving
The scheduled 50% cut in Bitcoin's block subsidy.
Hash Rate
The total computational power securing the network.
Mining
Producing new blocks by performing Proof of Work.
Nakamoto Consensus
Bitcoin's consensus rule: follow the chain with the most work.
Nonce
The number miners change while searching for a valid hash.
Proof of Work
A consensus mechanism that requires computational work to add blocks.
Confirmation
A block built on top of the block containing a transaction.
SPV (Simplified Payment Verification)
A way to verify Bitcoin transactions without downloading the full chain.
UTXO (Unspent Transaction Output)
Bitcoin's accounting model: balances as a set of unspent outputs.
Bitcoin
The first decentralised digital currency, launched in 2009.
BIP (Bitcoin Improvement Proposal)
A formal proposal to change Bitcoin.
Lightning Network
Bitcoin's payment-channel scaling layer.
Payment Channel
An off-chain ledger between two parties.
Mempool
The waiting room for unconfirmed transactions.
Fee Rate
Transaction fee per vbyte or per gas unit.
Satoshi (Unit)
The smallest unit of bitcoin: 0.00000001 BTC.
Satoshi Nakamoto
Bitcoin's pseudonymous creator.
SegWit (Segregated Witness)
A 2017 Bitcoin upgrade that separated signature data.
Taproot
Bitcoin's 2021 upgrade improving privacy and scripting.
Halving Cycle
Bitcoin's roughly four-year monetary cycle.
General
Altcoin
Any cryptocurrency that is not Bitcoin.
Cryptocurrency
Digital money secured by cryptography on a blockchain.
Stablecoin
A cryptocurrency designed to track a stable reference value.
CEX (Centralized Exchange)
A company-operated crypto trading venue.
Whitepaper
The technical document describing a protocol's design.
KYC (Know Your Customer)
Identity verification required by regulated services.
AML (Anti-Money Laundering)
Regulations preventing illicit financial flows.
Tokenomics
The economic design of a cryptocurrency.
Market Capitalization
Circulating supply × price.
ICO (Initial Coin Offering)
An early-stage token sale to fund a project.
WAGMI / NGMI
Crypto slang for community sentiment.
HODL
Holding through volatility instead of trading.
FUD (Fear, Uncertainty, Doubt)
Negative narratives that pressure prices and sentiment.
FOMO (Fear Of Missing Out)
Buying late because everyone else is winning.
Whale
A holder large enough to move markets.
Blockchain
Block
A bundle of transactions added to the blockchain.
Blockchain
A chained, append-only ledger of blocks.
Consensus Mechanism
The rules a network uses to agree on the canonical chain.
Fork
A divergence in the blockchain or its rules.
Node
A computer participating in the blockchain network.
Proof of Stake
A consensus mechanism where validators stake capital instead of burning energy.
Reorganization (Reorg)
Replacing recent blocks with a competing chain that has more work.
Transaction
A signed instruction that updates the blockchain state.
Block Time
Average interval between consecutive blocks.
Genesis Block
The first block in a blockchain.
Concepts
Decentralization
Distributing control across many independent participants.
Atomic Swap
Trustless cross-chain trade using hash time-locked contracts.
Bridge
A protocol that moves assets or messages between chains.
Byzantine Fault Tolerance (BFT)
A system that works even when some nodes lie or fail.
Staking
Locking tokens to secure a network and earn rewards.
Validator
A node that proposes and attests to blocks in PoS.
Layer 1 (L1)
A base blockchain network with its own consensus.
Layer 2 (L2)
A scaling network that settles to a Layer 1.
Rollup
An L2 that posts transaction data to L1 for security.
Optimistic Rollup
A rollup that assumes validity, with a fraud-proof challenge window.
ZK-Rollup
A rollup that proves validity with zero-knowledge cryptography.
Sidechain
A separate blockchain pegged to another via a bridge.
Soft Fork
A backwards-compatible protocol upgrade.
Hard Fork
A non-backwards-compatible protocol upgrade.
Peer-to-Peer Network
A network where every participant is both client and server.
Full Node
A node that validates every rule for itself.
Pruned Node
A full node that discards old block data after validation.
IPFS (InterPlanetary File System)
A content-addressed peer-to-peer file system.
Token Burn
Permanently removing tokens from supply.
Finality
The point at which a transaction is irreversible.
Uncle / Ommer Block
A valid block not included in the main chain (legacy Ethereum).
RPC (Remote Procedure Call)
The API wallets and dApps use to talk to a node.
Testnet
A test network with no real economic value.
Mainnet
The live production network.
Block Explorer
A search engine for blockchain data.
Ethereum
DeFi (Decentralized Finance)
Financial services built from smart contracts.
Ethereum
A programmable blockchain that supports smart contracts.
EVM (Ethereum Virtual Machine)
The execution environment for Ethereum smart contracts.
Gas
The unit measuring computational cost on Ethereum.
NFT (Non-Fungible Token)
A unique, non-interchangeable token on a blockchain.
Smart Contract
Code on a blockchain that automatically enforces its rules.
Solidity
The most popular programming language for Ethereum smart contracts.
Web3
An umbrella term for blockchain-based, user-owned internet applications.
DAO (Decentralized Autonomous Organization)
An on-chain organization governed by token holders.
dApp (Decentralized Application)
An app whose backend lives on a blockchain.
DEX (Decentralized Exchange)
A smart-contract-based trading protocol.
AMM (Automated Market Maker)
A pricing formula that replaces order books.
Liquidity Pool
A smart contract holding pooled assets for trading.
Impermanent Loss
Loss vs. holding when you provide AMM liquidity.
Yield Farming
Earning rewards by deploying capital across DeFi protocols.
Governance Token
A token that grants voting rights in a protocol.
ERC-20
The standard for fungible tokens on Ethereum.
ERC-721
The Ethereum standard for non-fungible tokens.
ERC-1155
A multi-token standard for fungible and NFT assets.
Gas Fee
What you pay to execute a transaction on Ethereum.
EIP-1559
Ethereum's fee market upgrade introducing base fee + tip.
The Merge
Ethereum's 2022 switch from Proof of Work to Proof of Stake.
Oracle
A service that brings off-chain data on-chain.
Chainlink
A leading decentralized oracle network.
MEV (Maximal Extractable Value)
Profit from reordering, inserting or censoring transactions.
Flash Loan
An uncollateralized loan repaid in the same transaction.
TVL (Total Value Locked)
Total assets deposited in a DeFi protocol.
APY (Annual Percentage Yield)
Compounded annual return on a deposit.
Airdrop
Free distribution of tokens to wallets meeting criteria.
ENS (Ethereum Name Service)
Human-readable names for Ethereum addresses.
MetaMask
The most widely used Ethereum browser wallet.
Cryptography
Digital Signature
A cryptographic proof that the holder of a private key authorised a message.
ECDSA
Elliptic Curve Digital Signature Algorithm.
Hash Function
A deterministic function mapping arbitrary input to fixed-size output.
Merkle Root
The single hash summarising all transactions in a block.
Merkle Tree
A binary tree of hashes used to summarise data efficiently.
Private Key
The secret number that authorises spending from an address.
Public Key
The shareable counterpart to a private key.
SHA-256
The hash function Bitcoin uses everywhere.
Zero-Knowledge Proof
Proving you know something without revealing what it is.
Schnorr Signature
A signature scheme enabling key aggregation.
Merkle Proof
Compact proof that a transaction is in a block.
Hash Function
A one-way function turning data into a fixed-size digest.
Collision Resistance
Property that makes hash functions trustworthy.
Elliptic Curve Cryptography (ECC)
The public-key cryptography behind blockchain wallets.
secp256k1
The elliptic curve Bitcoin and Ethereum use.
Security
Seed Phrase
A human-readable backup of a wallet's private keys.
Wallet
Software or hardware that manages your private keys.
51% Attack
An attack where one party controls majority hash power.
Cold Storage
Keeping private keys offline for security.
Custody
Who controls the private keys.
Slashing
Destroying part of a validator's stake as punishment.
Multi-Signature (Multisig)
A wallet requiring multiple keys to spend.
Hardware Wallet
A dedicated device that signs transactions offline.
Hot Wallet
A wallet whose keys live on an internet-connected device.
HD Wallet (BIP-32)
A wallet that derives many keys from one seed.
Address Reuse
Receiving multiple payments to the same address.
Rug Pull
A scam where developers abandon a project and run with funds.
Phishing
Tricking users into revealing keys or signing malicious transactions.
Scam (Crypto Scams)
Common fraud patterns targeting crypto users.
Smart Contract Audit
Expert review of contract code for vulnerabilities.
Browse all terms A–Z
Every term in the glossary, alphabetically. Click any entry to read its full definition with related links and an interactive learning path.
#
A
- Address (Bitcoin / Crypto Address) — A public destination for receiving cryptocurrency.
- Altcoin — Any cryptocurrency that is not Bitcoin.
- Atomic Swap — Trustless cross-chain trade using hash time-locked contracts.
- AMM (Automated Market Maker) — A pricing formula that replaces order books.
- Address Reuse — Receiving multiple payments to the same address.
- AML (Anti-Money Laundering) — Regulations preventing illicit financial flows.
- APY (Annual Percentage Yield) — Compounded annual return on a deposit.
- Airdrop — Free distribution of tokens to wallets meeting criteria.
B
- Block — A bundle of transactions added to the blockchain.
- Block Header — The metadata at the top of each block.
- Block Reward — New coins paid to the miner of a block.
- Blockchain — A chained, append-only ledger of blocks.
- Bitcoin — The first decentralised digital currency, launched in 2009.
- BIP (Bitcoin Improvement Proposal) — A formal proposal to change Bitcoin.
- Bridge — A protocol that moves assets or messages between chains.
- Byzantine Fault Tolerance (BFT) — A system that works even when some nodes lie or fail.
- Block Time — Average interval between consecutive blocks.
- Block Explorer — A search engine for blockchain data.
C
- Consensus Mechanism — The rules a network uses to agree on the canonical chain.
- Cryptocurrency — Digital money secured by cryptography on a blockchain.
- Confirmation — A block built on top of the block containing a transaction.
- CEX (Centralized Exchange) — A company-operated crypto trading venue.
- Cold Storage — Keeping private keys offline for security.
- Custody — Who controls the private keys.
- Chainlink — A leading decentralized oracle network.
- Collision Resistance — Property that makes hash functions trustworthy.
D
- Decentralization — Distributing control across many independent participants.
- DeFi (Decentralized Finance) — Financial services built from smart contracts.
- Difficulty — A parameter that controls how hard it is to mine a block.
- Digital Signature — A cryptographic proof that the holder of a private key authorised a message.
- Double Spend — Attempting to spend the same coin twice.
- DAO (Decentralized Autonomous Organization) — An on-chain organization governed by token holders.
- dApp (Decentralized Application) — An app whose backend lives on a blockchain.
- DEX (Decentralized Exchange) — A smart-contract-based trading protocol.
E
- ECDSA — Elliptic Curve Digital Signature Algorithm.
- Ethereum — A programmable blockchain that supports smart contracts.
- EVM (Ethereum Virtual Machine) — The execution environment for Ethereum smart contracts.
- ERC-20 — The standard for fungible tokens on Ethereum.
- ERC-721 — The Ethereum standard for non-fungible tokens.
- ERC-1155 — A multi-token standard for fungible and NFT assets.
- EIP-1559 — Ethereum's fee market upgrade introducing base fee + tip.
- Elliptic Curve Cryptography (ECC) — The public-key cryptography behind blockchain wallets.
- ENS (Ethereum Name Service) — Human-readable names for Ethereum addresses.
F
- Fork — A divergence in the blockchain or its rules.
- Fee Rate — Transaction fee per vbyte or per gas unit.
- Flash Loan — An uncollateralized loan repaid in the same transaction.
- Full Node — A node that validates every rule for itself.
- FUD (Fear, Uncertainty, Doubt) — Negative narratives that pressure prices and sentiment.
- FOMO (Fear Of Missing Out) — Buying late because everyone else is winning.
- Finality — The point at which a transaction is irreversible.
G
H
- Halving — The scheduled 50% cut in Bitcoin's block subsidy.
- Hash Function — A deterministic function mapping arbitrary input to fixed-size output.
- Hash Rate — The total computational power securing the network.
- Hard Fork — A non-backwards-compatible protocol upgrade.
- Hardware Wallet — A dedicated device that signs transactions offline.
- Hot Wallet — A wallet whose keys live on an internet-connected device.
- HD Wallet (BIP-32) — A wallet that derives many keys from one seed.
- Halving Cycle — Bitcoin's roughly four-year monetary cycle.
- Hash Function — A one-way function turning data into a fixed-size digest.
- HODL — Holding through volatility instead of trading.
I
K
L
M
- Merkle Root — The single hash summarising all transactions in a block.
- Merkle Tree — A binary tree of hashes used to summarise data efficiently.
- Mining — Producing new blocks by performing Proof of Work.
- Mempool — The waiting room for unconfirmed transactions.
- Multi-Signature (Multisig) — A wallet requiring multiple keys to spend.
- MEV (Maximal Extractable Value) — Profit from reordering, inserting or censoring transactions.
- Market Capitalization — Circulating supply × price.
- Merkle Proof — Compact proof that a transaction is in a block.
- MetaMask — The most widely used Ethereum browser wallet.
- Mainnet — The live production network.
N
O
P
- Private Key — The secret number that authorises spending from an address.
- Proof of Stake — A consensus mechanism where validators stake capital instead of burning energy.
- Proof of Work — A consensus mechanism that requires computational work to add blocks.
- Public Key — The shareable counterpart to a private key.
- Payment Channel — An off-chain ledger between two parties.
- Phishing — Tricking users into revealing keys or signing malicious transactions.
- Peer-to-Peer Network — A network where every participant is both client and server.
- Pruned Node — A full node that discards old block data after validation.
R
- Reorganization (Reorg) — Replacing recent blocks with a competing chain that has more work.
- Rollup — An L2 that posts transaction data to L1 for security.
- Rug Pull — A scam where developers abandon a project and run with funds.
- RPC (Remote Procedure Call) — The API wallets and dApps use to talk to a node.
S
- Seed Phrase — A human-readable backup of a wallet's private keys.
- SHA-256 — The hash function Bitcoin uses everywhere.
- Smart Contract — Code on a blockchain that automatically enforces its rules.
- Solidity — The most popular programming language for Ethereum smart contracts.
- SPV (Simplified Payment Verification) — A way to verify Bitcoin transactions without downloading the full chain.
- Stablecoin — A cryptocurrency designed to track a stable reference value.
- Staking — Locking tokens to secure a network and earn rewards.
- Slashing — Destroying part of a validator's stake as punishment.
- Sidechain — A separate blockchain pegged to another via a bridge.
- Satoshi (Unit) — The smallest unit of bitcoin: 0.00000001 BTC.
- Satoshi Nakamoto — Bitcoin's pseudonymous creator.
- Soft Fork — A backwards-compatible protocol upgrade.
- SegWit (Segregated Witness) — A 2017 Bitcoin upgrade that separated signature data.
- Schnorr Signature — A signature scheme enabling key aggregation.
- Scam (Crypto Scams) — Common fraud patterns targeting crypto users.
- secp256k1 — The elliptic curve Bitcoin and Ethereum use.
- Smart Contract Audit — Expert review of contract code for vulnerabilities.
T
- Transaction — A signed instruction that updates the blockchain state.
- The Merge — Ethereum's 2022 switch from Proof of Work to Proof of Stake.
- Taproot — Bitcoin's 2021 upgrade improving privacy and scripting.
- Tokenomics — The economic design of a cryptocurrency.
- TVL (Total Value Locked) — Total assets deposited in a DeFi protocol.
- Token Burn — Permanently removing tokens from supply.
- Testnet — A test network with no real economic value.
U
V
W
- Wallet — Software or hardware that manages your private keys.
- Web3 — An umbrella term for blockchain-based, user-owned internet applications.
- Whitepaper — The technical document describing a protocol's design.
- WAGMI / NGMI — Crypto slang for community sentiment.
- Whale — A holder large enough to move markets.
Y
Z
Browse by category
7 categories cover the entire blockchain stack — from base-layer protocols to application-layer concepts.
Bitcoin (25)
Address, Block, Block, Difficulty…
Blockchain (10)
Block, Blockchain, Consensus, Fork…
Concepts (25)
Decentralization, Atomic, Bridge, Byzantine…
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Digital, ECDSA, Hash, Merkle…
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DeFi, Ethereum, EVM, Gas…
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Seed, Wallet, 51%, Cold…
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