Source : Webster's Revised Unabridged Dictionary (1913)

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\, n. [OE. bulle, fr. L. bulla bubble, stud, knob,
   LL., a seal or stamp: cf. F. bulle. Cf. {Bull} a writing,
   {Bowl} a ball, {Boil}, v. i.]
   1. A seal. See {Bulla}.

   2. A letter, edict, or respect, of the pope, written in
      Gothic characters on rough parchment, sealed with a bulla,
      and dated ``a die Incarnationis,'' i. e., ``from the day
      of the Incarnation.'' See Apostolical brief, under
      {Brief}.

            A fresh bull of Leo's had declared how inflexible
            the court of Rome was in the point of abuses.
                                                  --Atterbury.

   3. A grotesque blunder in language; an apparent congruity,
      but real incongruity, of ideas, contained in a form of
      expression; so called, perhaps, from the apparent
      incongruity between the dictatorial nature of the pope's
      bulls and his professions of humility.

            And whereas the papist boasts himself to be a Roman
            Catholic, it is a mere contradiction, one of the
            pope's bulls, as if he should say universal
            particular; a Catholic schimatic.     --Milton.

   {The Golden Bull}, an edict or imperial constitution made by
      the emperor Charles IV. (1356), containing what became the
      fundamental law of the German empire; -- so called from
      its golden seal.

   Syn: See {Blunder}.

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.

Bull \Bull\, n. [OE. bule, bul, bole; akin to D. bul, G. bulle,
   Icel. boli, Lith. bullus, Lett. bollis, Russ. vol'; prob. fr.
   the root of AS. bellan, E. bellow.]
   1. (Zo["o]l.) The male of any species of cattle
      ({Bovid[ae]}); hence, the male of any large quadruped, as
      the elephant; also, the male of the whale.

   Note: The wild bull of the Old Testament is thought to be the
         oryx, a large species of antelope.

   2. One who, or that which, resembles a bull in character or
      action. --Ps. xxii. 12.

   3. (Astron.)
      (a) Taurus, the second of the twelve signs of the zodiac.
      (b) A constellation of the zodiac between Aries and
          Gemini. It contains the Pleiades.

                At last from Aries rolls the bounteous sun, And
                the bright Bull receives him.     --Thomson.

   4. (Stock Exchange) One who operates in expectation of a rise
      in the price of stocks, or in order to effect such a rise.
      See 4th {Bear}, n., 5.

   {Bull baiting}, the practice of baiting bulls, or rendering
      them furious, as by setting dogs to attack them.

   {John Bull}, a humorous name for the English, collectively;
      also, an Englishman. ``Good-looking young John Bull.''
      --W. D.Howells.

   {To take the bull by the horns}, to grapple with a difficulty
      instead of avoiding it.

Source : WordNet®

bull
     n 1: uncastrated adult male of domestic cattle
     2: a large and strong and heavyset man; "he was a bull of a
        man"; "a thick-skinned bruiser ready to give as good as he
        got" [syn: {bruiser}, {strapper}, {Samson}]
     3: obscene words for unacceptable behavior; "I put up with a
        lot of bullshit from that jerk"; "what he said was mostly
        bull" [syn: {bullshit}, {Irish bull}, {horseshit}, {shit},
         {crap}, {dogshit}]
     4: a serious and ludicrous blunder; "he made a bad bull of the
        assignment"
     5: uncomplimentary terms for a policeman [syn: {cop}, {copper},
         {fuzz}, {pig}]
     6: an investor with an optimistic market outlook; an investor
        who expects prices to rise and so buys now for resale
        later [ant: {bear}]
     7: (astrology) a person who is born while the sun is in Taurus
        [syn: {Taurus}]
     8: the second sign of the zodiac; the sun is in this sign from
        about April 20 to May 20 [syn: {Taurus}, {Taurus the Bull}]
     9: the center of a target [syn: {bull's eye}]
     10: a formal proclamation issued by the pope (usually written in
         antiquated characters and sealed with a leaden bulla)
         [syn: {papal bull}]
     11: mature male of various mammals of which the female is called
         `cow'; e.g. whales or elephants or especially cattle

bull
     v 1: push or force; "He bulled through his demands" [syn: {bull
          through}]
     2: try to raise the price of stocks through speculative buying
     3: talk through one's hat; "The politician was not well
        prepared for the debate and faked it" [syn: {bullshit}, {fake}]
     4: advance in price; "stocks were bulling"

Source : Free On-Line Dictionary of Computing

Bull
     
        {Bull Information Systems}