goosander vs merganser

goosander and merganser both are nouns.

Word	Noun	Adjective	Verb	Adverb
goosander	Yes	No	No	No
merganser	Yes	No	No	No

As nouns, merganser is a hypernym of goosander; that is, merganser is a word with a broader meaning than goosander:

goosander: common merganser of Europe and North America
merganser: large crested fish-eating diving duck having a slender hooked bill with serrated edges

Other hypernyms of goosander include fish duck, sawbill, sheldrake.

goosander (noun)	merganser (noun)
common merganser of Europe and North America	large crested fish-eating diving duck having a slender hooked bill with serrated edges