What is Blockchain ?
A blockchain can serve as “an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way.”[not in citation given (See discussion.)] For use as a distributed ledger, a blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which needs a collusion of the network majority.
Bitcoin is a worldwide cryptocurrency and digital payment system called the first decentralized digital currency, as the system works without a central repository or single administrator.
It was invented by an unknown person or group of people under the name Satoshi Nakamoto and released as open-source software in 2009.The system is peer-to-peer, and transactions take place between users directly, without an intermediary.These transactions are verified by network nodes and recorded in a public distributed ledger called a blockchain.
Lets watch video to understand it better ,