'awn' originates from Old English, specifically the word 'æfn' (or similar early forms), where the root referred to a bristle or beardlike appendage on grasses.

'awn' changed from Old English forms such as 'æfn' into Middle English forms like 'awne' and eventually became the modern English word 'awn'.

Initially, it meant a bristle- or beardlike projection on grasses, and over time it has retained this core botanical meaning.