WordNet (r) 3.0 (2006):

eiderdown
    n 1: a soft quilt usually filled with the down of the eider
         [syn: eiderdown, duvet, continental quilt]
    2: down of the eider duck

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "eiderdown":
   afghan, bed linen, bedclothes, bedcover, bedding, bedsheet,
   bedspread, blanket, blubber, breeze, buffalo robe, butter, case,
   clay, clothes, comfort, comforter, contour sheet, counterpane,
   cover, coverlet, coverlid, cushion, dough, down, feather bed,
   feathers, fitted sheet, fleece, floss, flue, fluff, foam, fur,
   fuzz, kapok, lap robe, linen, lint, patchwork quilt, pile, pillow,
   pillow slip, pillowcase, plush, pudding, puff, putty, quilt, robe,
   rubber, rug, satin, sheet, sheeting, silk, slip, spread, swansdown,
   thistledown, velvet, wax, wool, zephyr