Definition of eider in US English:


(also eider duck)


  • 1A northern sea duck, of which the male has mainly black and white plumage with a colored head, and the brown female has soft down feathers that are used to line the nest.

    Genus Somateria (and Polysticta), family Anatidae: four species, in particular the common eider (S. mollissima)

    • ‘Sea ducks like scoters and eiders are also divers.’
    • ‘Primary predators for these eiders were large gulls, and occasionally evidence of mammalian predation was found.’
    • ‘Terns and eiders had been disturbed, while eiders had been doubly hit because the pickers were depleting the mussel beds on which they feed.’
    • ‘They frequently nest in colonies, often in association with eiders.’
    • ‘Both of these types are plentiful on the Cape, as are sea ducks, such as scoters and eiders, viewable from many vantage points.’
    1. 1.1
      another term for eiderdown


Late 17th century: from Icelandic æthur, from Old Norse æthr.