Koterpillar

Name levels

At first, programs have objects from the problem domain - be it Song, Fruit or House.

Of course, you need abstractions - Object, Model, Class (and perhaps Metaclass) or Message. The customers aren't interested in these, but they are real words at least.

And when that is not enough, enter concepts named after publication authors: Kan extension, Yoneda lemma and Lie group. They don't have corresponding words in the language, so perhaps even the authors don't have hopes of their wide usage.

P.S. Of course, you can just name your types K1 and M1.