Home › Words › M › mergansermerganser/məˈɡænsə/merganser means any of various diving ducks of the genera Mergus or Lophodytes, which feed on fish and have a sharply serrated bill.merganser is pronounced /məˈɡænsə/.EtymologyFrom Late Latin merganser, from Latin mergus (“waterfowl, diver”), from mergō (“to dip, immerse”) + ānser (“goose”).nounAny of various diving ducks of the genera Mergus or Lophodytes, which feed on fish and have a sharply serrated bill.Definitions & examples from Wiktionary (CC BY-SA 3.0).