noun
1. : a plant of the genus Oenanthe ; especially : a European poisonous herb ( O. crocata ) having tuberous roots, a yellow juice that stains the skin, yellow flowers, and foliage resembling that of celery — compare water fennel
2. : a leafless herb ( Oxypolis canbyi ) of the southeastern United States with hollow leaflike stems and slender compound umbels of tiny white flowers