The Collaborative International Dictionary of English v.0.48:

Nutcracker \Nut"crack`er\, n.
   1. An instrument for cracking nuts.
      [1913 Webster]

   2. (Zool.)
      (a) A European bird (Nucifraga caryocatactes), allied to
          the magpie and crow. Its color is dark brown, spotted
          with white. It feeds on nuts, seeds, and insects.
      (b) The American, or Clarke's, nutcracker (Picicorvus
          Columbianus) of Western North America.
          [1913 Webster]

WordNet (r) 3.0 (2006):

nutcracker
    n 1: a compound lever used to crack nuts open
    2: any of various small short-tailed songbirds with strong feet
       and a sharp beak that feed on small nuts and insects [syn:
       nuthatch, nutcracker]
    3: speckled birds that feed on nuts