Exactly!

As I noted as an example: we use the term centaur to refer to a human/horse hybrid in mythology/fantasy. (Unless the biologists have been hiding something ...) In astronomy there is a group of stellar bodies that act like asteroid/comet hybrids and they're called Centaurs, the first found being named Chiron after the most famous and respected of centaurs.

So the query is: what is the rhetorical figure of speech equivalent to eponym or alliteration or metaphor for when you have used a name for one class of objects (yes, technically a centaur is sentient but think of it in the way human or chair is a class of object) as the given name for a wholly different group of objects.

Closest I've come is 'namesake' which I am convinced is NOT le mot juste.

Still looking! Thanks