Would it make more sense to think about private keys and public keys as a "lock and key" ?

A public key is your "lock" in that it stays open and public facing, everyone can see it, people can mess with it but to do anything useful with it you need the "key", your private key, needed to "open" the lock.

I dunno, maybe that language just makes things more complicated than they already are. Naming is such an important part of knowing.