that it is from PIE *bhln-, from base *bhel- (2) "to blow, swell" (see
bole). An uncastrated male, reared for breeding, as opposed to a bullock or steer. Extended after 1610s to males of other large animals (elephant, alligator, whale, etc.). Bullfrog is from 1738, on resemblance of voice. Stock market sense is from 1714. Bulldyke is from 1926 (see
dyke). Bullheaded "obstinate" is from 1818. Phrase to take the bull by the horns first recorded 1711.
bull"papal edict," c.1300, from L. bulla "sealed document" (cf. O.Fr. bulle, It. bulla), originally the word for the seal itself, from bulla "round swelling, knob," said ultimately to be from Gaulish, from PIE *beu-, a base supposed to have formed words associated with swelling (cf. Lith. bule "buttocks,"
M.Du. puyl "bag").