'handmaiden' originates from English compound formation in Middle English, combining 'hand' and 'maiden'.

'handmaiden' developed in Middle English from Old English elements: 'hand' (Old English 'hand') + 'maiden' (Old English 'mæden'), and the compound stabilized into the modern English 'handmaiden'.

Initially it referred specifically to a female servant kept 'at hand' for personal attendance; over time it has retained that primary sense but also gained a figurative sense meaning 'an instrument or subordinate agent' of something else.