The Collaborative International Dictionary of English v.0.48:

Bush \Bush\ (b[.u]sh), n. [OE. bosch, busch, buysch, bosk, busk;
   akin to D. bosch, OHG. busc, G. busch, Icel. b[=u]skr,
   b[=u]ski, Dan. busk, Sw. buske, and also to LL. boscus,
   buscus, Pr. bosc, It. bosco, Sp. & Pg. bosque, F. bois, OF.
   bos. Whether the LL. or G. form is the original is uncertain;
   if the LL., it is perh. from the same source as E. box a
   case. Cf. Ambush, Boscage, Bouquet, Box a case.]
   1. A thicket, or place abounding in trees or shrubs; a wild
      forest.
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   Note: This was the original sense of the word, as in the
         Dutch bosch, a wood, and was so used by Chaucer. In
         this sense it is extensively used in the British
         colonies, especially at the Cape of Good Hope, and also
         in Australia and Canada; as, to live or settle in the
         bush.
         [1913 Webster]

   2. A shrub; esp., a shrub with branches rising from or near
      the root; a thick shrub or a cluster of shrubs.
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            To bind a bush of thorns among sweet-smelling
            flowers.                              --Gascoigne.
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   3. A shrub cut off, or a shrublike branch of a tree; as,
      bushes to support pea vines.
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   4. A shrub or branch, properly, a branch of ivy (as sacred to
      Bacchus), hung out at vintners' doors, or as a tavern
      sign; hence, a tavern sign, and symbolically, the tavern
      itself.
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            If it be true that good wine needs no bush, 't is
            true that a good play needs no epilogue. --Shak.
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   5. (Hunting) The tail, or brush, of a fox.
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   To beat about the bush, to approach anything in a
      round-about manner, instead of coming directly to it; -- a
      metaphor taken from hunting.

   Bush bean (Bot.), a variety of bean which is low and
      requires no support (Phaseolus vulgaris, variety nanus).
      See Bean, 1.

   Bush buck, or Bush goat (Zool.), a beautiful South
      African antelope (Tragelaphus sylvaticus); -- so called
      because found mainly in wooden localities. The name is
      also applied to other species.

   Bush cat (Zool.), the serval. See Serval.

   Bush chat (Zool.), a bird of the genus Pratincola, of the
      Thrush family.

   Bush dog. (Zool.) See Potto.

   Bush hammer. See Bushhammer in the Vocabulary.

   Bush harrow (Agric.) See under Harrow.

   Bush hog (Zool.), a South African wild hog
      (Potamoch[oe]rus Africanus); -- called also bush pig,
      and water hog.

   Bush master (Zool.), a venomous snake (Lachesis mutus) of
      Guinea; -- called also surucucu.

   Bush pea (Bot.), a variety of pea that needs to be bushed.


   Bush shrike (Zool.), a bird of the genus Thamnophilus,
      and allied genera; -- called also batarg. Many species
      inhabit tropical America.

   Bush tit (Zool.), a small bird of the genus Psaltriparus,
      allied to the titmouse. Psaltriparus minimus inhabits
      California.
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WordNet (r) 3.0 (2006):

bush tit
    n 1: active grey titmice of western North America [syn:
         bushtit, bush tit]