'evenhandedness' originates from Modern English, specifically formed from the adjective 'evenhanded' plus the suffix '-ness', where 'even' meant 'level, equal' (from Old English 'efen') and 'hand(ed)' referred to 'having a particular kind of hand or manner' (from Old English 'hand').

'even' comes from Old English 'efen' meaning 'level'; 'hand' comes from Old English 'hand'. The compound adjective 'evenhanded' developed in Early Modern English by combining 'even' + 'handed', and the noun-forming suffix '-ness' was later added to produce 'evenhandedness'.

Initially it had a concrete sense related to being 'even-handed' (literally balanced or equal in hand/manner); over time it evolved into the abstract noun meaning 'impartiality' or 'fairness' used today.