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

Overgrown grass, weeds, bushes, vines, poison ivy or other vegetation allowed to grow tall can lead to rodents or give the impression that no one lives there, and attract crime, the town of of West Hartford warned in a notice to residents. —Sean Krofssik, Hartford Courant, 4 July 2025

The poison ivy was but a prologue for what came next, for what Jones worried would cost him not only his budget hike but also his left leg. —Grayson Haver Currin, Outside Online, 28 Mar. 2025

Here are different methods of getting rid of poison ivy and their pros and cons: When handling poison ivy, don’t neglect your gear. —Patricia Shannon, Southern Living, 17 June 2025

There was poison ivy in the front yard, the sidewalk had cracks, and there was garbage everywhere. —Celia Fernandez, CNBC, 31 May 2025

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