What is a blockchain in the bitcoin world

A block chain or blockchain is a distributed database that maintains a continuously growing list of data records that are hardened against tampering and revision, even by operators of the data store's nodes. The most widely known application of a block chain is the public ledger of transactions forcryptocurrencies originally used in bitcoin.^[1] This record is enforced cryptographically and hosted on machines working as data store's nodes.^[2]