Blockchain is digital ledger system in which transactions made in bitcoin or another cryptocurrency are digitally recorded chronologically and publicly whenever a cryptocurrency is bought or sold.
Existing on multiple computers at the same time, Blockchain constantly grows as new sets of recordings, or ‘blocks’, are added to it. Each block contains a timestamp and a link to the previous block, thereby forming a ‘Chain‘.
As distributed database aka Blockchain is not managed by any particular body instead everyone in the network gets a copy of the whole database. Old blocks are preserved forever and new blocks are added to the ledger irreversibly, making it impossible to manipulate by faking documents, transactions and other information.