Source : Webster's Revised Unabridged Dictionary (1913)

Coypu \Coy"pu\ (koi"p??), n. [Native name.] (Zo["o]l.)
   A South American rodent ({Myopotamus coypus}), allied to the
   beaver. It produces a valuable fur called nutria. [Written
   also {coypou}.]

Source : WordNet®

coypu
     n : aquatic South American rodent resembling a small beaver;
         bred for its fur [syn: {nutria}, {Myocastor coypus}]