late 14c., origin obscure, perhaps from O.Fr. buignete "a fritter," originally "boil, swelling," dim. of buigne "swelling from a blow, bump on the head," from a Gmc. source (cf. M.H.G. bunge "clod, lump"), or from Gaul. *bunia (cf. Gael. bonnach). Of hair coiled at the back of the head, first attested 1894. The first record of buns in the sense of "male buttocks" is from 1960s; but the singular form meant "tail of a hare" (1530s) in Scottish and northern England dialect and was transferred to human beings (and conveniently rhymed with nun in ribald ballads). This may be an entirely different word.