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

Similar elastic bands at the ankles make for a secure fit, perfect for pulling over socks in areas where the poison ivy or poison oak hasn’t died back yet or to limit your chances of ticks. —Alice Bennett, Travel + Leisure, 28 Sep. 2024

Like its cousins, poison oak and poison ivy, poison sumac contains urushiol in every part of the plant, but is more toxic. —Leanne Potts, Better Homes & Gardens, 28 Sep. 2024

Itching and stinging: Breast milk has been used on the skin to relieve the sting and itching of insect bites, bee stings, chicken pox, poison ivy, poison oak, and poison sumac. —Donna Murray, Rn, Parents, 29 July 2024

Common Types of Rashes and Conditions Treated Some of the common skin rashes and irritations that calamine lotion can help relieve include the following: Poison ivy/poison oak/poison sumac rash: These rashes are caused by oil from poisonous plants. —Megan Nunn, Pharmd, Verywell Health, 26 July 2024

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