The Collaborative International Dictionary of English v.0.48:

Down \Down\, n. [Akin to LG. dune, dun, Icel. d?nn, Sw. dun,
   Dan. duun, G. daune, cf. D. dons; perh. akin to E. dust.]
   1. Fine, soft, hairy outgrowth from the skin or surface of
      animals or plants, not matted and fleecy like wool; esp.:
      (a) (Zool.) The soft under feathers of birds. They have
          short stems with soft rachis and bards and long
          threadlike barbules, without hooklets.
      (b) (Bot.) The pubescence of plants; the hairy crown or
          envelope of the seeds of certain plants, as of the
          thistle.
      (c) The soft hair of the face when beginning to appear.
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                And the first down begins to shade his face.
                                                  --Dryden.
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   2. That which is made of down, as a bed or pillow; that which
      affords ease and repose, like a bed of down
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            When in the down I sink my head,
            Sleep, Death's twin brother, times my breath.
                                                  --Tennyson.
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            Thou bosom softness, down of all my cares!
                                                  --Southern.
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   Down tree (Bot.), a tree of Central America (Ochroma
      Lagopus), the seeds of which are enveloped in vegetable
      wool.
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