'malleolus' originates from Latin, specifically the word 'malleolus', where 'malleus' meant 'hammer' and the diminutive suffix '-olus' meant 'little'.

'malleolus' passed into New Latin and medical usage from Classical Latin and was then adopted into English as 'malleolus' with the regular plural 'malleoli'.

Initially it meant 'little hammer' (a diminutive of 'malleus'), but over time it came to denote the hammer-shaped bony protuberance at the ankle now called 'malleolus' (plural 'malleoli').