mule: English has two words mule. The ‘donkeylike animal’ [13] comes via Old French mul from Latin mūlus, which was borrowed from a pre- Latin language of the Mediterranean area; Albanian mušk ‘mule’ is related. Mule the ‘slipper’ [16] is probably an adaptation of Latin mulleus, which denoted a sort of red or purple shoe worn by high-ranking magistrates in Rome. This was short for mulleus calceus ‘red shoe’, and mulleus itself appears to have been derived from mullus ‘red mullet’ (ultimate source of English mullet [15]), which in turn came from Greek múllos, a relative of mélās ‘black’. => mullet[mule etymology, mule origin, 英语词源]