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

Smothering poison ivy is all about blocking off both light and oxygen sources the plant uses to thrive. —Patricia Shannon, Southern Living, 8 May 2026

Be careful of exposure when removing poison ivy. —Eva Flowe april 24, Charlotte Observer, 24 Apr. 2026

It’s often used to treat insect bites or poison ivy rashes. —Bestreviews, Chicago Tribune, 18 Mar. 2026

Think poison ivy, toxic mushrooms or a toad’s skin secretions. —Tiffany Acosta, AZCentral.com, 2 Mar. 2026

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 Toxicodendron (T. radicans synonym Rhus 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