The Collaborative International Dictionary of English v.0.48:

Floss \Floss\ (?; 195), n. [It. floscio flabby, soft, fr. L.
   fluxus flowing, loose, slack. See Flux, n.]
   1. (Bot.) The slender styles of the pistillate flowers of
      maize; also called silk.
      [1913 Webster]

   2. Untwisted filaments of silk, used in embroidering.
      [1913 Webster]

   3. A body feather of an ostrich. Flosses are soft, and gray
      from the female and black from the male.
      [Webster 1913 Suppl.]

   Floss silk, silk that has been twisted, and which retains
      its loose and downy character. It is much used in
      embroidery. Called also floxed silk.

   Floss thread, a kind of soft flaxen yarn or thread, used
      for embroidery; -- called also linen floss, and floss
      yarn. --McElrath.
      [1913 Webster]