| Noun | 1. woolly thistle - biennial Eurasian white hairy thistle having pale purple flowers; naturalized in North Americacotton thistle, Onopordon acanthium, Onopordum acanthium, Scotch thistlethistle - any of numerous plants of the family Compositae and especially of the genera Carduus and Cirsium and Onopordum having prickly-edged leavesgenus Onopordon, genus Onopordum, Onopordon, Onopordum - a genus of Eurasian herbs of the family Compositae with prickly foliage and large purplish flowers | | 2.woolly thistle - thistle of western North America having white woolly leavesCirsium flodmaniiplume thistle, plumed thistle - any of numerous biennial to perennial herbs with handsome purple or yellow or occasionally white flower headsCirsium eriophorum, European woolly thistle - woolly thistle of western and central Europe and Balkan Peninsula |