poison oak

noun

Any of the species of Toxicodendron with compound leaves having three oak-like leaflets, native to North America.

Similar
poison ivymarkweedToxicodendron radicansRhus radicans
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Meanings

nounpoison oak (usually uncountable, plural poison oaks)

plural poison oaks

  1. uncountableusuallyAny of the species of Toxicodendron with compound leaves having three oak-like leaflets, native to North America.

Synonyms & antonyms

nounclimbing plant common in eastern and central United States with ternate leaves and greenish flowers followed by white berries; yields an irritating oil that causes a rash on contact

Similar
poison ivymarkweedToxicodendron radicansRhus radicans
Broader
poisonous plant
Also see
markweedpoison ivy

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

Its leaves resemble those of the true oaks, and the leaves and twigs contain urushiol, which can cause allergic reactions.

Full word history & related roots →
Cite this entry
APA

poison oak. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/poison%20oak

MLA

“poison oak.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/poison%20oak. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “poison oak,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/poison%20oak.

Source: poison oak on Wiktionary, CC BY-SA 4.0.