any of various diving ducks, as the scaups, goldeneyes, scoters, and eiders, found principally on seas.
Origin of sea duck
First recorded in 1745–55
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
any of various large diving ducks, such as the eider and the scoter, that occur along coasts
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012