Howdy. Erlang's modules are involved in code namespace for the compiler & runtime (i.e., the 'M' of the 'MFA' triple of Module + Function name + Arity that names a function) as well being the unit/scope/bound for hot code loading (i.e., you must load or unload an entire module at a time).

I've worked in Erlang-land far longer than I've lived in any OOP-land, so I'm not sure what you mean by enterprise'y OOP. Coincidentally, Pony's rules for "Packages" are something I just smacked my ignorant head against a few hours ago. The subsections of https://tutorial.ponylang.org/packages/ in the tutorial can probably answer at least some of your question: specifically "Package System" and "Use Statement".

I'm not sure which features of Erlang modules you're interested in comparing to Pony classes, but I'll take a stab at trying to answer.

Pony classes are defined using a "class" keyword. Classes have properties and functions, where functions are like methods that you would find in a language like Java. Pony supports structural subtyping via interfaces and nominal subtyping via traits, and it disallows multiple inheritance.

I'm not sure how much that helps, but if you have more specific questions I'd be happy to try to answer them. I'm a little rusty on my Erlang, but hopefully it will come back to me.