Source : Webster's Revised Unabridged Dictionary (1913)

Muscovy duck \Mus"co*vy duck`\ [A corruption of musk duck.]
   (Zo["o]l.)
   A duck ({Cairina moschata}), larger than the common duck,
   often raised in poultry yards. Called also {musk duck}. It is
   native of tropical America, from Mexico to Southern Brazil.

Source : WordNet®

muscovy duck
     n : large crested wild duck of Central America and South
         America; widely domesticated [syn: {musk duck}, {Cairina
         moschata}]