Oh thanks, that's fascinating, I thought they were the same thing. Reading the answers on that page, it sounds like there are quite a few programs in common use (e.g. Final Cut Pro) that treat ENTER and RETURN differently. I have both keys on this PC clone keyboard plugged into a Mac mini, so maybe I'll be able to use the numpad's ENTER for keyboard shortcuts. Thank you!
Your comment would have had more relevance 30 years ago but these days I think it's fine to use the terms interchangeably given 99.99999% of software these days use those keys interchangeably.