Bitcoin glossary
Understand Bitcoin from the first block to mining, halvings and payment channels. Follow the definitions to see how the network fits together.
Bech32
An error-detecting address encoding introduced for native SegWit Bitcoin outputs.
Bitcoin
A peer-to-peer monetary network whose native asset is bitcoin, commonly abbreviated BTC.
Bitcoin Script
Bitcoin's stack-based language for expressing transaction-output spending conditions.
Block reward
The total amount a Bitcoin miner may claim from a valid block's subsidy and transaction fees.
Block weight
The consensus measure of Bitcoin block capacity introduced with SegWit.
Change output
An output returning the unused portion of a Bitcoin transaction's inputs to the sender.
Coinbase transaction
The first transaction in a Bitcoin block, used to claim the permitted mining reward.
Fee rate
A transaction fee expressed per unit of transaction size or weight-derived size.
Halving
Bitcoin's scheduled reduction of the block subsidy by half every 210,000 blocks.
Hashrate
The number of hash calculations performed per second by mining hardware or a mining network.
HODL
Crypto slang for keeping an asset instead of selling it, especially through market turbulence.
Mining
The process of searching for valid proof-of-work blocks and publishing successful candidates.
Mining difficulty
A measure of how demanding it is to find a valid proof-of-work block hash.
Mining pool
A group of miners that coordinates work and distributes rewards under a shared payout scheme.
PSBT
Partially Signed Bitcoin Transaction: a format for exchanging transaction data between wallets and signers.
Replace by fee
A transaction-relay mechanism allowing an eligible pending transaction to be replaced by a higher-fee alternative.
Satoshi
The smallest unit of bitcoin used in ordinary onchain accounting: one hundred millionth of a BTC.
SegWit
A Bitcoin upgrade that separates transaction witness data from the traditional transaction serialization.
Stale block
A valid block that is no longer part of the chain selected by the network's fork-choice rule.
Taproot
A Bitcoin output design that combines key-based spending with optional committed script paths.
Timelock
A condition that prevents a transaction or output from being spent before a specified time or block constraint.
Transaction ID
A transaction identifier computed from the transaction's protocol-defined serialized data.
Transaction input
A component of a Bitcoin transaction that identifies an earlier output being spent.
Transaction malleability
The ability to alter a transaction's identifier without changing its intended payment effect.
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