Pronunciation: (hel'u-bôr", -bōr"),[key] —n. 1. any of several plants of the genus Helleborus, of the buttercup family, having basal leaves and clusters of flowers, esp. H. niger, the Christmas rose.
2. any of various plants of the genus Veratrum. Cf. false hellebore. 3. any of several poisonous or medicinal substances obtained from these plants.