Tube amp terminology

According to someone I spoke all good phono amps are pure class A push pull triode. That started me thinking, what does that even mean?

I do not own any tube amp nor will I own any tube amps in the foreseeable future. But I am curious about the terminology. When reading forums I read terms lie: cathode follower, triode, pentode, tetrode, OTL, push pull, SET, class A, class A/B, auto bias, negative feedback, zero feed feedback etc

So can someone here please explain tube amps to me? I know some of these terms are not solely used for tube amps.