The top result is Wikipedia, "Web3, also known as Web 3.0,[1][2][3] is an idea for a new iteration of the World Wide Web that incorporates decentralization based on blockchains.[4]"

And even then, with federated services you still usually aren't hosting your content, that's really closer to what web 1.0 was, imo.

I guess the term is still nascent enough for it's meaning to be in flux. Hopefully good people are pushing it to align with the best tendencies