musk duck vs muscovy duck

musk duck and muscovy duck both are nouns.

Word	Noun	Adjective	Verb	Adverb
musk duck	Yes	No	No	No
muscovy duck	Yes	No	No	No

As nouns, musk duck and muscovy duck are synonyms defined as:

musk duck and muscovy duck: large crested wild duck of Central America and South America; widely domesticated

Other synonyms of musk duck include Cairina moschata.

musk duck (noun)	muscovy duck (noun)
large crested wild duck of Central America and South America; widely domesticated	large crested wild duck of Central America and South America; widely domesticated