A well-known animal, powerful, fierce, and violent. The name may have originated from the sign of a shop or inn, as "John at the Bull." Bul, in Saxon, is a brooch, a stud, a bracelet.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.

BULL. A very natural sobriquet, as well as a common inn-sign, and a frequent heraldric charge. It may, however, be a personal name, as the forms Bole, Bolle, &c., arc found in Domesd. The corresponding names Taureau, Torel, Tyrel, Torelli, BuUe, &c., are plentiful on the continent. Let no Frenchman, however, think that " John Bull" is tbe commonest of designations iu England, for in the Loud. Direct, of 1852, I find only four people so called.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.