Merriam-Webster Collegiate Dictionary - teasel

 I. noun  Etymology: Middle English tesel, from Old English t?sel; akin to Old English t?san to tease  Date: before 12th century  1.  a. an Old World prickly herb (Dipsacus fullonum of the family Dipsacaceae, the ~ family) with flower heads that are covered with stiff hooked bracts and were used especially formerly in the woolen industry — called also fuller's ~  b. a plant of the same genus as the ~  2.  a. a flower head of the fuller's ~ used when dried to raise a nap on woolen cloth  b. a wire substitute for the ~  II. transitive verb  (~ed or ~led; ~ing or ~ling)  Date: 1543 to nap (cloth) with ~s