A block is a data structure that forms the blockchain and is used to record all transactions taking place in the network. Unlike a conventional centralized database, a blockchain is a distributed database made up of several blocks, each block containing a record of a certain number of transactions.
Each block in the blockchain records transactions after they have been verified or validated by a network node. After the data validation process, a block is closed and added to the blockchain. The update in the blockchain’s state is then broadcast by the node which produced the block to ensure that all nodes have the most updated version of the blockchain record at their end.
The data stored in a single block on a blockchain is cryptographically secured. A block is identified by a long string of numbers and can contain transaction data from the previous block.