Block

A block is a data structure in blockchain technology that stores a batch of transactions, which have been validated by the network's consensus mechanism. In Bitcoin and many other blockchains, each block contains a cryptographic hash of the previous block, a timestamp, and the transaction data. These blocks are chained together to form the blockchain, creating an immutable and transparent ledger of transactions. A block is "mined" or "validated" when a network participant (e.g., a miner in a proof-of-work system) successfully solves a cryptographic puzzle, adding the block to the blockchain. For example, in Bitcoin, miners compete to solve the puzzle, and the first to succeed gets rewarded with newly minted Bitcoin. Blocks play a crucial role in maintaining the integrity and transparency of decentralized systems like Bitcoin and Ethereum.