A seemingly ordinary computer file for storing transaction data, which can be aggregated with others to form a blockchain.
A block is one of the basic units of a blockchain, along with nodes. In itself, the block is only a computer file that is used to store the information of a transaction, especially the parties involved, a time stamp, and records of previous transaction blocks which take the form of a cryptographic hash. When placed in a logical sequence with other blocks, this computer file eventually forms a blockchain with the individuals or machines coordinating the transactions serving as the nodes on the network.
Blocks are the core elements of the blockchain revolution. Without them, the idea of a distributed ledger, peer-to-peer (P2P) payment networks, and other terms and concepts associated with the world of cryptocurrencies will fall apart.