What is a Blockchain?

The Short Explanation:

Blockchain is type of a decentralised database that is shared throughout a network of nodes or computers. Once data, or a new block, has been added to the chain, it can never be altered – this means the blockchain is immutable.

In the case of Bitcoin, the blockchain technology is used as a decentralised public ledger that shows all Bitcoin transactions. This greatly increases transparency and makes the Cryptocurrency more secure.

It is worth noting though that not all blockchains are decentralised, there are some single entities that own all the computers on the network.