"a plant," Old English wyrt "root, herb, vegetable, plant, spice," from Proto-Germanic *wurtiz (cognates: Old Saxon wurt, Old Norse, Danish urt, Old High German wurz "plant, herb," German Wurz, Gothic waurts, Old Norse rot "root"), from PIE root *wrad- "twig, root" (see radish). St. John's wort attested from 15c.