poison oak

noun
Updated on: 21 Mar 2018

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.
2 : poison ivy 1a

Recent Examples of poison oak from the Web

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.

First Known Use of poison oak

1739

in the meaning defined at sense 1

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POISON OAK Defined for English Language Learners

poison oak

Definition of poison oak for English Language Learners

  • : 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 Defined for Kids

poison oak

noun

Definition of poison oak for Students

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

Medical Dictionary

poison oak

noun \ -ˈōk \

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
2 : poison ivy 1a
3 : a skin rash produced by poison oak

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to treat with excessive attention

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