The Collaborative International Dictionary of English v.0.48:

Skein \Skein\, n. [OE. skeyne, OF. escaigne, F. ['e]cagne,
   probably of Celtic origin; cf. Ir. sgainne, Gael. sgeinnidh
   thread, small twine; or perhaps the English word is
   immediately from Celtic.]
   1. A quantity of yarn, thread, or the like, put up together,
      after it is taken from the reel, -- usually tied in a sort
      of knot.
      [1913 Webster]

   Note: A skein of cotton yarn is formed by eighty turns of the
         thread round a fifty-four inch reel.
         [1913 Webster]

   2. (Wagon Making) A metallic strengthening band or thimble on
      the wooden arm of an axle. --Knight.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Skein \Skein\, n. (Zool.)
   A flight of wild fowl (wild geese or the like). [Prov. Eng.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

skein
    n 1: coils of worsted yarn