There is some argument about terminology, whether the notion of blockchain includes the peer-to-peer distribution and consensus mechanism (eg proof-of-work) or not. (In my view, it shouldn't.)

Git uses a somewhat extended version of a blockchain (a directed acyclic graph instead of just a linked list).

I think it's a cool technology, and has many applications where you want an immutable sequence of records. But it's not a panacea, and the current hype is overblown.