"The blockchain consists of a decentralized distributed database of blocks of data. In the case of bitcoin, the data is that of transactions people make between each other. Transactions are represented by data of person A, sending to person B, amount X. The transaction request between person A and B are linked through a hash of characters in one block, that references a hash in another block. These blocks are then linked in a network to chain them together as one larger ledger of all the data."

• from What is the Blockchain, Blockchain 2.0, and Steemit? Building the Future!

Simpler?

The blockchain is a record of data, such as transactions between people, that can't be tampered with or changed, because the data is distributed in many areas unlike current companies that store data in one place. It's really safe and secure.

I guess that's the simplest?