After a brief chat with dkg on the IRC channel, I should be changing the terminology a little bit:
I always use "OpenPGP certificates" (though i'll introduce the other terms as well) because i think the legacy terminology is an active obstacle to understanding
a public key is a mathematical object
a certificate binds together public key(s) and user id(s) with some types of cryptographically-verifiable certifications
if you start saying that a certificate *is* both a public key and *contains* a public key, and then you wonder why your readers are confused, it seems like the answer is right there
So, what I'm suggesting I do is I'm going to change all instances of where we'd normally use "Public Key" in normal parlance (or in reference to those blocks of text we download off the keyserver) as "OpenPGP Certificate."
I'd also like to open up the discussion for any other terminology that might be confusing, if anyone's got input or ideas.