Aid
late Middle English: from Old French aide (noun), aidier (verb), based on Latin adjuvare, from ad- ‘towards’ + juvare ‘to help’.
wiktionary
From Middle English aide, eide, ayde, from Old French eide, aide, from aidier, from Latin adiūtō, adiūtāre(“to assist, help”). Cognates include Spanish ayuda, Portuguese ajuda and Italian aiuto.
From Middle English aiden, from Old French eider, aider, aidier, from Latin adiuto, frequentative of adiuvō(“"assist"”, verb).
etymonline
aid (n.)
early 15c., "war-time tax," also "help, support, assistance," from Old French aide, earlier aiudha "aid, help, assistance" (9c.), from Late Latin adiuta, noun use of fem. of adiutus, past participle of Latin adiuvare "to give help to," from ad "to" (see ad-) + iuvare "to help, give strength, support, sustain," which is from a PIE source perhaps related to the root of iuvenis "young person" (see young (adj.)). Meaning "thing by which assistance is given" is recorded from 1590s; meaning "person who assists, helper" is from 1560s. Meaning "material help given by one country to another" is from 1940.
aid (v.)
"to assist, help," c. 1400, from Old French aidier "help, assist" (Modern French aider), from Latin adiutare, frequentative of adiuvare (past participle adiutus) "to give help to," from ad "to" (see ad-) + iuvare "to help, assist, give strength, support, sustain," which is from a PIE source perhaps related to the root of iuvenis "young person" (see young (adj.)). Related: Aided; aiding.
