n. 1. (Bot.) The masterwort (Peucedanum Ostruthium), a tall and coarse European umbelliferous plant. [ 1913 Webster ]
2. (Bot.) A biennial weed in Europe and America having large pinnate leaves and yellow flowers and a bitter and somewhat poisonous root; the ancestor of cultivated parsnip; called also wild parsnip. [ WordNet 1.5 ]