Bull Bull, v. i. To be in heat; to manifest sexual desire as cows do. [Colloq.], Bull Bull, v. t. (Stock Exchange) To endeavor to raise the market price of; as, to bull railroad bonds; to bull stocks; to bull Lake Shore; to endeavor to raise prices in; as, to bull the market. See 1st Bull, n., 4., Bull Bull, a. Of or pertaining to a bull; resembling a bull; male; large; fierce. Bull bat (Zo["o]l.), the night hawk; -- so called from the loud noise it makes while feeding on the wing, in the evening. Bull calf. (a) A stupid fellow. Bull mackerel (Zo["o]l.), the chub mackerel. Bull pump (Mining), a direct single-acting pumping engine, in which the steam cylinder is placed above the pump. Bull snake (Zo["o]l.), the pine snake of the United States. Bull stag, a castrated bull. See Stag. Bull wheel, a wheel, or drum, on which a rope is wound for lifting heavy articles, as logs, the tools in well boring, etc.