'axletree' originates from Middle English, specifically the word 'axeltre', where 'axel' (from Old English 'eaxel') meant 'axle' and 'tre' (from Old English 'trēow') meant 'tree' or 'wood' (a wooden shaft).

'axletree' changed from the Middle English word 'axeltre' and eventually became the modern English word 'axletree' (a compound of 'axle' + 'tree').

Initially, it meant 'a wooden axle', but over time it evolved into its current meaning of 'an axle or shaft for a wheel' without necessarily implying that it is made of wood.