This is a debate over semantics, let's conclude by presenting our competing definitions. A blockchain is ledger shared between multiple computers. Entries in t

This is a debate over semantics, let's conclude by presenting our competing definitions. A blockchain is ledger shared between multiple computers. Entries in this ledger contain the cryptographic hash of the previous entry, creating an append-only data structure where existing records cannot be modified. While blockchains are generally used in p2p and open networks, this isn't a requirement. Bitcoin was a blockchain when Nakamoto was the only node. Popularity and openness are not required to meet this technical definition.