Blockchain these days is mostly a hype train terminology. There are three components that come together to make a blockchain, but people will often call their technology blockchain if it meets only some of theses:

1. Merkle tree or some other cryptographic append-only technology. (This is really old, by the way).

2. Proof-of-work. (This was, to my knowledge, first proposed as an anti-spam measure, which incidentally went nowhere because most spammers "borrow" other people's computers for free, and so it doesn't inconvenience them in the slightest).

3. Achieving consensus by saying that he who did the most work is right. (This, again to my knowledge, was actually the main innovation that Bitcoin brought to the table).

Many people pitch things only having the Merkle tree as being blockchain technology, because blockchain is in and Merkle trees are so 20th century technology.