(a) A plant of the genus Carduus, the common thistle;— sometimes used in nontechnical texts for any plant with sharp prickles; also in fig. contexts; also coll. [quot. a1500 Diseases Women(3)]; a crop of thistles [quot. ?a1425]; ~ blosme, the flower of the thistle; thistel(es doun, the pappus of the thistle; (b) chiefly in glossaries and medical texts: a plant not of the genus Carduus but usu. characterized by prickles; thisteles dust, ?powdered root of bryony; ?bleched ~, brod (unbrode) ~, mete ~, oure ladie ~, smal ~, various kinds of thistle or thistle-like plants; fou ~, q.v.; holi ~, ?blessed thistle Cnicus benedictus; ?holy or milk thistle Silybum marianum; hors ~, ?a kind of wild lettuce ?Lactuca virosa or ?Lactuca serriola; se ~, water caltrop Tribulus marinus; soue ~, q.v.; thou ~, q.v.; wode ~ [see wod(e n.(2)]; (c) in surnames and place names [see Smith PNElem.2.204].