The Collaborative International Dictionary of English v.0.48:

Sprout \Sprout\ (sprout), v. i. [imp. & p. p. Sprouted; p. pr.
   & vb. n. Sprouting.] [OE. sprouten, spruten; akin to
   OFries. spr[=u]ta, AS. spre['o]tan, D. spruiten, G.
   spriessen, Sw. spruta to squirt, to spout. Cf. Sprit, v. t.
   & i., Sprit a spar, Spout, v. t., Spurt.]
   1. To shoot, as the seed of a plant; to germinate; to push
      out new shoots; hence, to grow like shoots of plants.
      [1913 Webster]

   2. To shoot into ramifications. [Obs.] --Bacon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sprout \Sprout\, v. t.
   1. To cause to sprout; as, the rain will sprout the seed.
      [1913 Webster]

   2. To deprive of sprouts; as, to sprout potatoes.
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The Collaborative International Dictionary of English v.0.48:

Sprout \Sprout\, n. [Cf. AS. sprote a sprout, sprig; akin to
   Icel. sproti, G. sprosse. See Sprout, v. i.]
   1. The shoot of a plant; a shoot from the seed, from the
      stump, or from the root or tuber, of a plant or tree; more
      rarely, a shoot from the stem of a plant, or the end of a
      branch.
      [1913 Webster]

   2. pl. Young coleworts; Brussels sprouts. --Johnson.
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   Brussels sprouts (Bot.) See under Brussels.
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WordNet (r) 3.0 (2006):

sprout
    n 1: any new growth of a plant such as a new branch or a bud
    2: a newly grown bud (especially from a germinating seed)
    v 1: produce buds, branches, or germinate; "the potatoes
         sprouted" [syn: shoot, spud, germinate, pullulate,
         bourgeon, burgeon forth, sprout]
    2: put forth and grow sprouts or shoots; "the plant sprouted
       early this year" [syn: sprout, stock]

Moby Thesaurus II by Grady Ward, 1.0:

125 Moby Thesaurus words for "sprout":
   accrue from, adventurer, arise, arise from, be contingent on,
   be due to, begin, bine, bloom, blossom, bough,
   bourgeois gentilhomme, branch, branchedness, branchiness, brew,
   bud, bud from, burgeon, burst forth, come from, come out of,
   come up, deadwood, depend on, derive from, descend from, develop,
   emanate from, emerge from, ensue from, filiation, flagellum,
   flourish, flow from, flower, follow from, fork, frond, gather,
   gemmate, germinate, germinate from, grow, grow from, grow out of,
   grow rank, grow up, hang on, hinge on, hypertrophy, increase,
   issue from, leaf, leaf out, leave, limb, luxuriate, mature,
   mushroom, name-dropper, newly-rich, nouveau riche,
   nouveau roturier, offset, offshoot, originate in, outgrow,
   overdevelop, overgrow, overrun, overtop, parvenu, pig in clover,
   proceed from, procreate, pullulate, put forth, put forth leaves,
   put out buds, ramage, ramification, reproduce, riot, root, runner,
   sapling, sarment, scion, seedling, set, shoot, shoot up, slip,
   social climber, spear, spray, sprig, spring from, spring up, sprit,
   sprout from, sprout up, status seeker, stem from, stolon,
   strike root, sucker, switch, take root, tendril, thallus, thrive,
   tower, tufthunter, turn on, twig, upshoot, upspear, upspring,
   upsprout, upstart, vegetate, wax, would-be gentleman