Refactoring is mostly...

I'll point out that I don't think I've ever heard that term before, and I'm in the IT field (though not closely related to programmers). Anyway, keep in mind that your resume is going to be looked at more by HR people than by tech people. As such, you might want to steer clear of non-popular jargon. You want the HR person to understand what you did. That's not to say that you shouldn't include some to make sure the tech people get it one they get their hands on it, but your first job is to make sure that it gets past the HR person to them.