'boon' originates from Old Norse, specifically the word 'bón', where 'bón' meant 'request, prayer'.

'boon' changed from Old English/Old Norse words such as Old English 'bēn' and Old Norse 'bón' (both meaning 'petition' or 'request') and eventually became the modern English word 'boon' with the sense of a benefit or favor.

Initially, it meant 'request' or 'petition', but over time it evolved into its current common meaning of 'benefit' or 'blessing'.