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

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 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'poison oak.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1739, in the meaning defined at sense 1

Time Traveler
The first known use of poison oak was in 1739

Dictionary Entries Near poison oak

Cite this Entry

“Poison oak.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/poison%20oak. Accessed 4 Jun. 2023.

Kids Definition

poison oak

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

Medical Definition

poison oak

noun
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
3
: a skin rash produced by poison oak

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