Synonyms for Poison Oak (same or very similar meaning)
WordNet sense 1 (climbing plant common in eastern and central United States with ternate leaves and greenish flowers followed by white berries; yields an irritating oil that causes a rash on contact):
markweed, poison ivy, poison mercury, Rhus radicans, Toxicodendron radicansFrom the ODE community, based on WordNetadd/edit