The Collaborative International Dictionary of English v.0.48:

Grosbeak \Gros"beak\, n. [Gross + beak: cf. F. gros-bec.]
   (Zool.)
   One of various species of finches having a large, stout beak.
   The common European grosbeak or hawfinch is Coccothraustes
   vulgaris.
   [1913 Webster]

   Note: Among the best known American species are the
         rose-breasted (Habia Ludoviciana); the blue (Guiraca
         c[oe]rulea); the pine (Pinicola enucleator); and the
         evening grosbeak. See Hawfinch, and Cardinal
         grosbeak, Evening grosbeak, under Cardinal and
         Evening. [Written also grossbeak.]

WordNet (r) 3.0 (2006):

grosbeak
    n 1: any of various finches of Europe or America having a
         massive and powerful bill [syn: grosbeak, grossbeak]