- poison oak - dermatitis resulting from contact with a poison oak plant
--1 is a kind of Rhus dermatitis
- poison ivy, markweed, poison mercury, poison oak, Toxicodendron radicans, Rhus radicans - 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
--2 is a kind of poisonous plant
--2 is a member of Toxicodendron, genus Toxicodendron - poison ivy, markweed, poison mercury, poison oak, Toxicodendron radicans, Rhus radicans - 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