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 pubescens synonym Rhus toxicodendron) chiefly of the southeastern U.S.

2

: poison ivy sense 1a

Examples of poison oak in a Sentence

Recent Examples on the Web

The cave also isn't a simple walk in a park, as the conservancy also describes potential hazards such as poison oak, falling rocks, and even rattlesnakes and bees. —Staff Author, Travel + Leisure, 29 Apr. 2025

In some cases, your dog won’t react to a plant, but can transfer an allergen to you, like in the case of poison oak and poison ivy. —Amelia Arvesen, Outside Online, 5 Apr. 2025

Keep an eye out, though, for poison oak, as it’s found throughout the canyon. —Jaclyn Cosgrove, Los Angeles Times, 3 Apr. 2025

See where So, please don't eat poison oak — and try using one of these eight problem plants with your meal instead. —Brandi D. Addison, Austin American-Statesman, 4 June 2024

Word History

First Known Use

1739, in the meaning defined at sense 1

Rhymes for poison oak

• artichoke
• nanticoke
• womenfolk
• awoke
• baroque
• bespoke
• colloque
• convoke
• evoke
• invoke
• keystroke
• kinfolk

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