The Collaborative International Dictionary of English v.0.48:

Lamb \Lamb\, n. [AS. lamb; akin to D. & Dan. lam, G. & Sw. lamm,
   OS., Goth., & Icel. lamb.]
   1. (Zool.) The young of the sheep.
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   2. Any person who is as innocent or gentle as a lamb.
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   3. A simple, unsophisticated person; in the cant of the Stock
      Exchange, one who ignorantly speculates and is victimized.
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   Lamb of God, The Lamb (Script.), the Jesus Christ, in
      allusion to the paschal lamb.
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            The twelve apostles of the Lamb.      --Rev. xxi.
                                                  14.
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            Behold the Lamb of God, which taketh away the sin of
            the world.                            --John i. 29.

   Lamb's lettuce (Bot.), an annual plant with small obovate
      leaves (Valerianella olitoria), often used as a salad;
      corn salad. [Written also lamb lettuce.]

   Lamb's tongue, a carpenter's plane with a deep narrow bit,
      for making curved grooves. --Knight.

   Lamb's wool.
      (a) The wool of a lamb.
      (b) Ale mixed with the pulp of roasted apples; -- probably
          from the resemblance of the pulp of roasted apples to
          lamb's wool. [Obs.] --Goldsmith.
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The Collaborative International Dictionary of English v.0.48:

Lamb \Lamb\, v. i. [imp. & p. p. Lambed; p. pr. & vb. n.
   Lambing.]
   To bring forth a lamb or lambs, as sheep.
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WordNet (r) 3.0 (2006):

lamb
    n 1: young sheep
    2: English essayist (1775-1834) [syn: Lamb, Charles Lamb,
       Elia]
    3: a person easily deceived or cheated (especially in financial
       matters)
    4: a sweet innocent mild-mannered person (especially a child)
       [syn: lamb, dear]
    5: the flesh of a young domestic sheep eaten as food
    v 1: give birth to a lamb; "the ewe lambed"