poison oak


Definition of poison oak

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.

Examples of poison oak in a Sentence

Recent Examples on the Web

California Porterville: Visitors to Sequoia National Forest in the southern Sierra Nevada area are being cautioned about the growth of a native plant that can cause severe irritation similar to poison oak and poison ivy. USA TODAY, "Rocket’s last blast, Alaska drought, million-dollar ham: News from around our 50 states," 23 Aug. 2019 Like poison ivy, poison oak causes a similar uncomfortable reaction due to the urushiol oils present on the plant. Caroline Picard, Good Housekeeping, "QUIZ: Can You Identify These Dangerous Summer Plants and Bugs?," 3 Aug. 2018 There are posted warnings at the site for everything from rattlesnakes to poison oak, but nothing about the shootings. Carter Evans, CBS News, "Police probe whether campsite death is linked to a string of unsolved shootings," 29 June 2018 According to the American Skin Association, poison ivy and poison oak cause the most common allergic reactions in the United States, affecting as many as 50 million Americans a year. Erik Polan, Philly.com, "Q&A: How do I know if I have poison ivy?," 8 June 2018 Eco-Goats, which offers its services to clear invasive species, overgrown brush and difficult-to-handle plants such as poison ivy, poison oak and brambles, has been in business for about 10 years. Marissa J. Lang, Washington Post, "‘They’re kind of mesmerizing’: These nine goats draw spectators while clearing an overgrown Maryland park," 25 May 2018 Chronic itch is different from chemical itch, which occurs when the immune system reacts to a foreign substance, such as oil from a poison oak leaf or saliva in a mosquito bite. Emily Underwood, Science | AAAS, "Why getting old gives you itchy skin," 3 May 2018 The area is also home to black bears, rattlesnakes, and poison oak, in addition to the more friendly deer and otters. Sunset, "7 Best BLM Camping Spots," 22 Jan. 2018 Some law enforcement officials surmised that Richardson, who suffered from bipolar disorder, walked into the canyon, took off her clothes and succumbed to anaphylactic shock from extensive poison oak exposure. Alexander Nazaryan, Newsweek, "Lie and Deny: Secrecy and Suspicion Surround the Los Angeles County Sheriff’s Department," 21 Apr. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'poison oak.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of poison oak

1739, in the meaning defined at sense 1

Keep scrolling for more

Learn More about poison oak

Statistics for poison oak

Last Updated

4 Sep 2019

Look-up Popularity

Time Traveler for poison oak

The first known use of poison oak was in 1739

See more words from the same year

Keep scrolling for more

More Definitions for poison oak

poison oak


English Language Learners Definition of poison oak

: a common bush in the western U.S. that causes a very itchy and painful rash on your skin if you touch it

poison oak


Kids Definition of poison oak

: a bush related to poison ivy that can cause an itchy painful rash when touched

poison oak

\ -ˈōk How to pronounce poison oak (audio) \

Medical Definition of poison oak

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
3 : a skin rash produced by poison oak

More from Merriam-Webster on poison oak

Rhyming Dictionary: Words that rhyme with poison oak

Britannica.com: Encyclopedia article about poison oak

Comments on poison oak

What made you want to look up poison oak? Please tell us where you read or heard it (including the quote, if possible).


fear of the number 13

Get Word of the Day daily email!

Test Your Vocabulary

Where in the World? A Quiz

  • peter bruegel tower of babel painting
  • What language does pajama come from?
True or False

Test your knowledge - and maybe learn something along the way.

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!