The Collaborative International Dictionary of English v.0.48:

Crossbill \Cross"bill`\, n. (Zool.)
   A bird of the genus Loxia, allied to the finches. Their
   mandibles are strongly curved and cross each other; the
   crossbeak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Crossbill \Cross"bill`\ (-b[i^]l`). (Law)
   A bill brought by a defendant, in an equity or chancery suit,
   against the plaintiff, respecting the matter in question in
   that suit. --Bouvier.
   [1913 Webster]

   Note: In criminal practice, cross bills of indictment for
         assault, in which the prosecutor in once case is the
         defendant in another, may be tried together.
         [1913 Webster]

WordNet (r) 3.0 (2006):

crossbill
    n 1: finch with a bill whose tips cross when closed [syn:
         crossbill, Loxia curvirostra]