The Collaborative International Dictionary of English v.0.48:

Wishing \Wish"ing\,
   a. & n. from Wish, v. t.
   [1913 Webster]

   Wishing bone. See Wishbone.

   Wishing cap, a cap fabled to give one whatever he wishes
      for when wearing it.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wishbone \Wish"bone`\, n.
   The forked bone in front of the breastbone in birds; --
   called also merrythought, and wishing bone. See
   Merrythought, and Furculum.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wishing bone
    n 1: the furcula of a domestic fowl [syn: wishbone, wishing
         bone]