poison ivy

noun

1

a

: a climbing plant (Toxicodendron radicans synonym Rhus radicans) of the cashew family that is especially common in the eastern and central U.S., that has ternate leaves, greenish flowers, and white berries, and that produces an 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

Illustration of poison ivy

• poison ivy 1a

Examples of poison ivy in a Sentence

I got poison ivy all over my arm.

Recent Examples on the Web

For example, diverse species such as poison ivy, cashews and mangoes all belong to the same extensive family. —Newsweek, 18 Dec. 2024

Common triggers include poison ivy, metals commonly found in jewelry like nickel, and ingredients in cosmetics or laundry detergent. —Laura Baisas, Popular Science, 30 Jan. 2025

Some allergens, like poison ivy, frequently cause blisters for most people who come in contact with them. —Laura Schober, Health, 27 Dec. 2024

Causes of Allergic Blisters Contact dermatitis, a common allergic reaction, occurs when the skin comes into contact with substances like poison ivy, nickel, or certain cosmetics. —Laura Schober, Health, 27 Dec. 2024

Word History

First Known Use

1782, in the meaning defined at sense 1a

Kids Definition

poison ivy

noun

1

: a usually climbing plant that is related to the sumacs, has leaves usually with three leaflets, greenish flowers, white berries, and leaves and stems that when bruised and touched may cause an itching rash on the skin

2

: a skin rash caused by poison ivy

Medical Definition

poison ivy

noun

-ˈī-vē 

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 sense 1b

2

: a skin rash produced by poison ivy