'axil' originates from Latin, specifically the word 'axilla', where 'axilla' meant 'armpit' (a diminutive form related to 'axis').

'axil' changed from Medieval Latin 'axilla' into Middle English forms such as 'axill' and eventually became the modern English word 'axil'.

Initially, it meant 'armpit' in Latin, but over time it came to be used in English for the 'armpit-like angle' of a plant (the angle between a leaf and its stem).