early 14c., "whalebone," from O.Fr. balaine (12c.) "whale, whalebone," from L. ballaena, from Gk. phallaina "whale" (apparently related to phallos "swollen penis," probably because of a whale's shape), from PIE base *bhel- (2) "to swell" (see bole). Klein writes that the Greek to Latin transition was "through the medium of the Illyrian language, a fact which explains the transition of Gk. -ph- into L. -b- (instead of -p-)."