[1] : The Collaborative International Dictionary of English v.0.48

teasel \tea"sel\, n. oe. tesel, as. t=aesel, t=aesl, 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 dipsacus 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.
      1913 webster

   note: small teasel is dipsacus pilosus, wild teasel is
         dipsacus sylvestris.
         1913 webster

   2. a bur of this plant.
      1913 webster

   3. any contrivance intended as a substitute for teasels in
      dressing cloth.
      1913 webster

   teasel frame, a frame or set of iron bars in which teasel
      heads are fixed for raising the nap on woolen cloth.
      1913 webster
see also:
tease tassel tazel teasle teazel teazle 
dipsacus dipsacus fullonum dipsacus pilosus dipsacus sylvestris teasel frame 

[2] : WordNet (r) 2.0

dipsacus sylvestris
     n : european teasel with white to pink flowers; naturalized in
         united states syn: wild teasel
see also:
wild teasel 

Sylvestris >> S Words
Sylvestris, definition of term: Sylvestris
sylvestris_pag1.html

Dipsacus >> D Words
Dipsacus, definition of term: Dipsacus
dipsacus_pag1.html