> For their own good reasons, mathematicians use "functor" as a concrete noun. Haskell copied this, hence how often you hear about "a functor".

> However, interfaces are adjectives that describe a data structure, which is why in many languages they are often named with -able suffixes (Iterable, Serializable, etc.) Programmers are better off thinking of it as Functable or Fmapable or something like that.

Fmapable makes much more sense to me. Naming is hard.