'awn' originates from Old English, broadly from a West Germanic source meaning 'bristle, beard' (early forms represented the idea of a hairlike projection).

'awn' appeared in Old English forms and continued into Middle English with little change (Middle English forms such as 'aun'/'awn'), eventually becoming the modern English 'awn'.

Initially it meant 'a bristle or beardlike projection on a plant'; over time the meaning has largely remained the same and is still used in botanical contexts to denote those hairlike structures.