'first-aid' originates from English, specifically a compound of the words 'first' and 'aid', where 'first' traces to Old English 'fyrst' meaning 'foremost' and 'aid' comes via Old French 'aide' (from Latin 'adiutare') meaning 'help'.

'first' developed from Old English 'fyrst' and 'aid' from Old French 'aide' (derived from Latin 'adiutare'); the compound 'first-aid' emerged in modern English usage (late 19th to early 20th century) as organized practices and kits for immediate care became common.

Initially it simply meant 'primary or first help'; over time it narrowed to specifically denote emergency medical care given immediately and the associated kits/training.