Source : Webster's Revised Unabridged Dictionary (1913)

Godchild \God"child`\, n.
   One for whom a person becomes sponsor at baptism, and whom he
   promises to see educated as a Christian; a godson or
   goddaughter. See {Godfather}.

Source : WordNet®

godchild
     n : an infant who is sponsored by an adult (the godparent) at
         baptism
     [also: {godchildren} (pl)]