poison oak

noun

either of two shrubs, Rhus toxicodendron, of the eastern U.S., or R. diversiloba, of the Pacific coast of North America, resembling poison ivy and causing severe dermatitis when touched by persons sensitive to them.
Also called poison ivy.

Origin of poison oak

An Americanism dating back to 1735–45

Words nearby poison oak

poison dogwood, poison gas, poison haw, poison hemlock, poison ivy, poison oak, poison pill, poison sumac, poison sumach, poison-arrow frog, poison-pen

Example sentences from the Web for poison oak

British Dictionary definitions for poison oak

poison oak

noun

either of two North American anacardiaceous shrubs, Rhus toxicodendron or R. diversiloba, that are related to the poison ivy and cause a similar rash See also sumach (def. 1)
(not in technical use) another name for poison ivy

Medical definitions for poison oak

poison oak

n.

Either of two shrubs, Rhus toxicodendron of the southeast United States or R. diversiloba of western North America, related to poison ivy and causing a rash on contact.
poison ivy