ˈīdə(r) noun
( -s )
Etymology: Dutch, German, or Swedish, from Icelandic æthur, from Old Norse æthr; akin to Swedish dialect åd, åda eider duck
1. or eider duck : any of several large northern sea ducks constituting Somateria and related genera and being distinguished by the profuse fine soft down that forms an insulating layer protecting the body from cold, that is used by the female for lining the nest, and that is eagerly sought by man resulting in near extinction of the birds in some areas
2. : eiderdown 1