Wouldn’t “sound editing” be, well, the editing of the audio? In conjunction with the editing of the image? Like, you put one bang here, and then another bang three seconds later. There, you’ve done some sound editing.
Not exactly.
JEDIT: this seems to explain it pretty well https://www.google.com/amp/s/mobile.nytimes.com/2018/03/02/movies/sound-mixing-sound-editing-explainer.amp.html