Blockchain is something like a database. It differs with database due to the way it stores information. Unlike a literal database, blockchain stores data in block that are chained together. The blocks are chained to one another in a chronological order. So fat blockchain has been used as the backbone for the trending cryptocurrency market.
Types of blockchains:
Public blockchains like Bitcoin and Ethereum.
Private blockchains like Hyperledger and R3 Corda.
Hybrid blockchains like Dragonchain.