[robenkleene]

The technical answer is layers and destructive edits, you could probably summarize this as compositing (i.e., combining different images together). I don't think there's necessarily even a correlation between pro vs. non-pro (I'm not remotely a pro, but run into limitations of the Lightroom-approach to editing [which is what you're talking about, editing that can't do destructive edits or non-adjustment layers] quickly). I think what it correlates with is whether you want to quickly edit lots of photos (Lightroom) or deeply edit a single photo without limitations (Photoshop).