What is Blockchain ?
Blockchain is basically a decentralised ledger which keeps the records of transactions chronologically. It records transactions like the exchange of money, property, or anything related to an enforceable contract or authorised access.
The term decentralisation means that multiple, independent machines are running copies of the blockchain ledger at once. Each recorded transaction is broadcasted to all the decentralized ledger copies.
When new transactions are registered, they are compiled in batches called "blocks" at regular time intervals; the blocks are created via the process called "mining" and added to the end of the "chain" of all the existing blocks, hence the technology is termed Blockchain.
The transactions recorded in the decentralized ledgers or Blockchains are verified by double-checking with the rest of the ledgers. The very existance of blocks allows every user to verify the fact that every specific transaction has indeed taken place at a specific moment in time.
In short, Blockchain is an unchangable, indisputable, openly accessible ledger of all transactions which have happened in a network since its inception.