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ei·der·downalso eider down (ī′dər-doun′)
1. The down of the eider, used as stuffing for quilts and pillows.
2. A quilt stuffed with the down of the eider.
3. A warm napped fabric.
[Swedish ejderdun, from Icelandic ædhar-dún : ædhar, genitive of ædhr, eider (from Old Norse ǣdhr) + dún, down (from Old Norse dūnn).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.