adderwort
/ˈadəwəːt/Now chiefly English regional and historical
noun
(A) The plant bistort, Persicaria bistorta; also called snakeweed; compare adder's grass.
Origin
Old English; earliest use found in Pseudo-Apuleius' Herbarium. Cognate with or formed similarly to Old Saxon nādarwort dragon arum (Middle Low German nāderwort, adderwort bistort, wild arum), Old High German nātarwurz dragon arum (German Natterwurz bistort, dragon arum; also Old High German nātarūnwurz from the Germanic base of adder + the Germanic base of wort.