- a toxic, liquid, catechol derivative, the active irritant principle in several species of the plant genus Rhus, as in poison ivy.
Origin of urushiol
1910–15; < Japanese urushi lacquer + -ol1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- a poisonous pale yellow liquid occurring in poison ivy and the lacquer tree
from Japanese urushi lacquer + -ol ²
- A toxic substance constituting the active allergen of the irritant oil present in poison ivy, poison oak, and poison sumac.
- A toxic substance present in the resin or on the surface of plants of the genus Rhus (syn. Toxicodendron). Urushiol is a mixture of several derivatives of catechol and is the irritating substance in poison ivy.
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