poison oak

noun

1

: any of several plants related to poison ivy and producing an oil with similar irritating properties: such as

a

: a bushy plant (Toxicodendron diversilobum synonym Rhus diversiloba) of the Pacific coast

b

: a bushy plant (Toxicodendron toxicarium synonym Rhus toxicodendron) chiefly of the southeastern U.S.

2

: poison ivy sense 1a

Example Sentences

Recent Examples on the Web

Are poison oak and poison ivy the same? —Camille Fine, USA TODAY, 22 June 2022

What are the symptoms of a poison oak rash? —Madison Yauger, Health.com, 28 June 2021

Poison Sumac Poison sumac is similar to poison ivy and poison oak in terms of having the poisonous oily resin called urushiol. —Chandra Fleming, Detroit Free Press, 15 Mar. 2023

Therapeutic properties ascribed to the sulfur and other minerals in the springs include supposedly helping cure skin diseases, digestive disorders, arthritis, sore muscles, and poison oak. —Perri Ormont Blumberg, Travel + Leisure, 10 Feb. 2023

Urushiol is also found in poison oak and poison ivy. —Emilie Le Beau Lucchesi, Discover Magazine, 1 Sep. 2022

Watch for poison oak, swift rapids, slick rock, and burning sun. —Chris Van Leuven, Outside Online, 19 Oct. 2022

The worst hazard for a person on the hunt for the Hyperion might be a bad case of poison oak. —Gale Holland, Los Angeles Times, 2 Aug. 2022

This sap, which is also found in poison oak and poison sumac, is called urushiol and can cause a severe rash that lingers for weeks. —Rachel Nall, Msn, SELF, 15 July 2022

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Word History

First Known Use

1739, in the meaning defined at sense 1

Kids Definition

poison oak

noun

: any of several shrubby plants related to poison ivy and causing a similar rash

Medical Definition

poison oak

noun

-ˈōk 

1

: any of several plants included in the genus Rhus or sometimes in the genus Toxicodendron that produce an irritating oil like that of poison ivy:

a

: a bushy plant (R. diversiloba synonym T. diversilobum) of the Pacific coast

b

: a bushy plant (R. toxicodendron synonym T. pubescens) of the southeastern United States

2

: poison ivy sense 1a

3

: a skin rash produced by poison oak