The Collaborative International Dictionary
Sea duck
Sea duck \Sea" duck`\ (Zo["o]l.) Any one of numerous species of ducks which frequent the seacoasts and feed mainly on fishes and mollusks. The scoters, eiders, old squaw, and ruddy duck are examples. They may be distinguished by the lobate hind toe.
Wiktionary
sea duck
n. (alternative spelling of seaduck English)
WordNet
sea duck
n. any of various large diving ducks found along the seacoast: eider; scoter; merganser
Usage examples of "sea duck".
I carried the consecrated down of a sea duck to scatter upon the sacrificial victim.