Core blockchain and cryptocurrency network terms, including blocks, transactions, nodes, mempool, forks, confirmations and other concepts.

Smart Contract

A blockchain program that executes predefined logic and manages on-chain state.

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Chain Reorganization

A replacement of part of the current chain with an alternative accepted history.

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Orphan Block

A block that has been excluded from the currently accepted chain.

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Soft Fork

A blockchain rule change that introduces stricter validity requirements.

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Blockchain

A distributed ledger built from a sequence of cryptographically linked blocks.

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Fork

A protocol-rule change or divergence between blockchain histories.

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Mempool

A collection of pending transactions waiting for block inclusion.

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Consensus Mechanism

A set of rules defining how a network selects and validates blocks.

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Consensus

The process of reaching agreement on valid blockchain state and history.

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Light Node

A node designed to operate with reduced storage and processing requirements.

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Full Node

A node capable of independently validating blockchain data against protocol rules.

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Blockchain Node

A network participant that performs blockchain data, validation, or communication functions.

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Stale Block

A valid competing block that remains outside the current main chain.

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Hard Fork

A protocol change that introduces rules incompatible with the previous rule set.

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Transaction Fee

A fee associated with processing and including a transaction in the blockchain.

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Transaction Output

A UTXO transaction element that creates funds for future spending.

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Transaction Input

A reference to a previous unspent output used by a new transaction.

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Transaction

A signed operation that changes blockchain state according to network rules.

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Block Weight

A protocol-specific metric used to determine the effective size of a block.

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Block Size

The amount of data contained in an individual blockchain block.

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Block Time

A time-based measure describing block production or a block timestamp.

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Block Height

A number identifying the position of a block in the chain.

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Block Header

The metadata portion of a block used for identification and validation.

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Genesis Block

The first block of a blockchain and the starting point of its history.

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Block

A blockchain data unit containing transactions and chain metadata.

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