A Eurasian perennial herb (Polygonum bistorta) having cylindrical spikes of usually pink flowers and a rhizome used as an astringent in folk medicine.
Any of certain related plants of the genus Polygonum.
[French bistorte, from Old French, from Medieval Latin *bistorta : Latin bis, twice; see bis + torta, past participle of torquēre, to twist; see torque1.]