Source : Webster's Revised Unabridged Dictionary (1913)

Chef-d'oeuvre \Chef`-d'[oe]uvre"\, n.; pl. {Chefs-d'[oe]uvre}.
   [F.]
   A masterpiece; a capital work in art, literature, etc.

Source : WordNet®

chef-d'oeuvre
     n : the most outstanding work of a creative artist or craftsman
         [syn: {masterpiece}]