https://www.hardforking.com/what-is-blockchain-a-simple-explanation/
A simple definition of Blockchain please...
Ummm, errr ok, it is a decentralized thingy that records your data on lots of computers, no hang on, that’s not correct. It is a distributed database that you raise money with, wait no, it is where Bitcoin comes from, sort of, right? Ok, now we have cleared that up for you we can move on. Find more definitions of Blockchain in this article, just case you are still confused.
Bonus! It comes with a super funny video :)