an adult male bovine animal
an adult male elephant, whale, or other large animal
somebody who resembles a bull in aggressiveness, strength, or brawny build
somebody who buys securities or commodities in expectation of a price rise or who acts to effect such a rise: compare bear1
(the Bull) the constellation and sign of the zodiac Taurus
Brit a bull's-eye
like a bull in a china shop
clumsy or tactless
take the bull by the horns
to face up to a problem
[Old English bula; (sense 3) prob developed as a companion to bear]