Definition
A block is a unit of data added to a blockchain. It typically groups transactions together with metadata needed to verify and connect them to earlier history. The exact fields differ by protocol. A block is not simply a folder of payments: its contents must satisfy the network’s validity rules.
How It Works
A miner or validator proposes a block according to the network’s consensus process. Other nodes check its structure, transactions and connection to the existing chain. In many designs, the block header includes a reference derived from the preceding block, creating a cryptographic link through time. Competing valid proposals may temporarily exist until the consensus rules determine the accepted history.
Uses and Limitations
Blocks help order transactions and provide a common record for participants. Block height indicates a block’s position, whereas block time concerns the interval between blocks. Inclusion in a block does not always mean immediate irreversible settlement; confirmation and finality depend on the protocol. Capacity limits and demand can also affect which pending transactions are included and the fees users offer.