Source : Webster's Revised Unabridged Dictionary (1913)

Teasel \Tea"sel\, n. [OE. tesel, AS. t?sel, t?sl, the fuller's
   herb. See {Tease}.] [Written also {tassel}, {tazel},
   {teasle}, {teazel}, and {teazle}.]
   1. (Bot.) A plant of the genus {Dipsacus}, of which one
      species ({D. fullonum}) bears a large flower head covered
      with stiff, prickly, hooked bracts. This flower head, when
      dried, is used for raising a nap on woolen cloth.

   Note: Small teasel is {Dipsacus pilosus}, wild teasel is {D.
         sylvestris}.

   2. A bur of this plant.

   3. Any contrivance intended as a substitute for teasels in
      dressing cloth.

   {Teasel frame}, a frame or set of iron bars in which teasel
      heads are fixed for raising the nap on woolen cloth.

Teasel \Tea"sel\, v. t. [imp. & p. p. {Teaseled}or {Teaselled};
   p. pr. & vb. n. {Teaseling} or {Teaselling}.]
   To subject, as woolen cloth, to the action of teasels, or any
   substitute for them which has an effect to raise a nap.

Source : WordNet®

teasel
     n : any of several herbs of the genus Dipsacus native to the Old
         World having flower heads surrounded by spiny bracts
         [syn: {teazel}, {teasle}]
     [also: {teaselling}, {teaselled}]