poison sumac or any of various poison ivy plants (esp. Rhus toxicodendron and R. diversiloba)
- Either of two plants, Toxicodendron pubescens, a shrub of the southeast United States, or T. diversilobum, a shrub or vine of western North America, having compound leaves with three lobed or toothed leaflets, and causing a rash on contact.
- See poison ivy.
- A skin rash caused by contact with one of these plants.
western poison oak
(usually uncountable, plural poison oaks)
- Any of the species of Toxicodendron with oak-like compound leaves, with three leaflets, native to North America.