poison oak

American  

noun

1. either of two shrubs, Rhus toxicodendron, of the eastern United States, or R. diversiloba, of the Pacific coast of North America, resembling poison ivy and causing severe dermatitis when touched by persons sensitive to them.

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poison oak British  

noun

1. either of two North American anacardiaceous shrubs, Rhus toxicodendron or R. diversiloba, that are related to the poison ivy and cause a similar rash See also sumach

2. (not in technical use) another name for poison ivy

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Etymology

Origin of poison oak

An Americanism dating back to 1735–45

Example Sentences

Plenty of cow patties, though, and a few patches of poison oak, which turns up often near Big Sur trails.

From Los Angeles Times

The group rested at the waterfall, including one hiker who put his hand on some poison oak.

From Los Angeles Times

“My feet were torn and oozing within my elk leather boots, and every inch of my skin was a rash of poison oak. Hours before I had been incapacitated by muscle cramps.”

From Los Angeles Times

Rangers describe the trail — a steep half-mile to reach the cave, then a half-mile loop inside — as “strenuous,” featuring possible encounters with poison oak, bees, rattlesnakes and falling rocks.

From Los Angeles Times

Poodle-dog isn’t a household name like poison oak and ivy, likely due to its limited geographic region and fleeting nature.

From Los Angeles Times