'even-leafed' originates from English, combining 'even' (from Old English 'efen', meaning 'level' or 'equal') and 'leaf' (from Old English 'lēaf'), with the adjectival suffix '-ed' forming a descriptor meaning 'having even leaves'.

'even' evolved from Old English 'efen' to Middle English 'even'; 'leaf' evolved from Old English 'lēaf' to Middle English 'leaf'. The compound adjective 'even-leafed' is a modern English formation combining these elements to describe leaf characteristics.

Initially the components meant 'level/equal' and 'leaf'; over time the compound came to be used specifically (especially in botanical contexts) to mean 'having leaves or leaflets arranged evenly or in paired (even) form'.