[oo-roo-shee-awl, -ol]
a toxic, liquid, catechol derivative, the active irritant principle in several species of the plant genus Rhus, as in poison ivy.

1910–15; < Japanese urushi lacquer + -ol

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To urushiol
World English Dictionary
urushiol (ˈuːrʊʃɪˌɒl, uːˈruː-)
a poisonous pale yellow liquid occurring in poison ivy and the lacquer tree
[from Japanese urushi lacquer + -ol²]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
American Heritage
Medical Dictionary

urushiol u·ru·shi·ol (u-rōō'shē-ôl', -ōl')
A toxic substance constituting the active allergen of the irritant oil present in poison ivy, poison oak, and poison sumac.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
American Heritage
Science Dictionary
urushiol   (-r'shē-ôl', -ōl')  Pronunciation Key 
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Example sentences
The cause is an oil called urushiol that occurs both on the leaves and stems
  and adheres to the skin.
Breaking the blisters releases urushiol oil that can spread.
Every part of the plant contains an oil called urushiol that inflames skin and
  results in painfully itchy blisters and rashes.
All parts of the plant contain a toxic resin called urushiol that causes skin
  and mucous membrane irritation.
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature