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.-a bur of this plant.-any contrivance intended as a substitute for teasels in dressing cloth.-to subject, as woolen cloth, to the action of teasels, or any substitute for them which has an effect to raise a nap.