What is the difference between sauce and dressing? Their purpose seems to be the same.
Dressing and sauce each have several non-overlapping senses in which they differ. The noun dressing has meanings "Material applied to a wound for protection or therapy", "Something added to the soil as a fertilizer etc.", a scolding ("dressing down"), and "The activity of getting dressed", as well as "A sauce, especially a cold one for salads." The noun sauce has meanings like booze ("on the sauce") and impertinence or sauciness ("answered back with sauce") among others, besides "a liquid (often thickened) condiment or accompaniment to food."