any of a genus (Helleborus) of poisonous Eurasian herbs of the buttercup family having showy flowers with petaloid sepals; also : the dried rhizome of a hellebore (such as H. niger) formerly used in medicine
hellebore
noun(hel-le-bore)
a poisonous herb (genus Veratrum) of the lily family; also : the dried rhizome of a hellebore (V. album or V. viride) that is used as an insecticide and contains toxic alkaloids that are cardiac and respiratory depressants