poison ivy

poison ivy

noun

Definition of POISON IVY

1

a : a climbing plant (Toxicodendron radicans syn. Rhus radicans) of the cashew family that is especially common in the eastern and central United States, that has ternate leaves, greenish flowers, and white berries, and that produces an acutely irritating oil causing a usually intensely itching skin rash

b : any of several plants closely related to poison ivy

2

: a skin rash caused by poison ivy

Examples of POISON IVY

1. I got poison ivy all over my arm.

Illustration of POISON IVY

First Known Use of POISON IVY

1784

poison ivy

noun \-ˈī-vē\   (Medical Dictionary)

Medical Definition of POISON IVY

1

a : a climbing plant of the genus Rhus (R. radicans synonym Toxicodendron radicans) that is especially common in the eastern and central United States, that has leaves in groups of three, greenish flowers, and white berries, and that produces an acutely irritating oil causing a usually intensely itching skin rash b : any of several plants closely related to poison ivy; especially : poison oak 1b

2

: a skin rash produced by poison ivy

Illustration of POISON IVY

poison ivy

noun    (Concise Encyclopedia)

Poison ivy (Toxicodendron radicans)—Walter Chandoha

Either of two North American species of white-fruited woody vines or shrubs of the sumac, or cashew, family. The species found in eastern North America (Toxicodendron radicans) is abundant; a western species, known as poison oak, is less common. Both species are sometimes classified as genus Rhus. A key identifier is leaves with three mitten-shaped leaflets. Contact with urushiol, an oil produced by the plant, can cause severe inflammation and blistering of human skin. Urushiol may be carried from the plant on clothing, shoes, tools, or soil; by animals; or by smoke from burning plants. Because urushiol is nonvolatile, a reaction may result from wearing clothing a year or more after its contact with the plant.