'applesauce' originates from English, specifically a compound of the words 'apple' and 'sauce' (where 'apple' comes from Old English 'æppel' and 'sauce' from Old French 'sauce').

'applesauce' was formed in English by joining 'apple' + 'sauce'; 'sauce' itself came into English via Old French 'sauce' from Latin 'salsa', and 'apple' comes from Old English 'æppel' (from Proto-Germanic *aplaz).

Initially it referred straightforwardly to a sauce or purée made from apples; over time it also developed a slang sense meaning 'nonsense' or 'rubbish'.