I would say that plaintext is correct. if password "secret123" is sent to you, it doesn't matter if it was sent via carrier pigeon, locked up in a secure brief

I would say that plaintext is correct. if password "secret123" is sent to you, it doesn't matter if it was sent via carrier pigeon, locked up in a secure briefcase and delivered by someone driving an aston martin, or via a TLS channel. It's still plaintext, because the receiver now has the actual password, and not a hash of the password.