The main thing I'm trying to answer is this: What are the distinguishing features between a "new feature" and a "product enhancement" when it comes to software development? Specifically, when applied to Scrum.
Here are some possible criteria that come to mind:
The other possibility is that I'm thinking about this all wrong and there's better, clearer terminology that should be used.
I guess this cannot be answered in a generally accepted way. However this is how I would put it:
A feature is new functionality i.e. a user can do something new with the software. An enhancement makes doing something that was possible before simpler, more powerful or adds somehow to existing functionality.