Definition of urushiol in English:



mass nounBiochemistry
  • An oily liquid which is the main constituent of Japanese lacquer and is responsible for the irritant properties of poison ivy and other plants. It consists of a mixture of catechol derivatives.

    • ‘For people who are sensitive to urushiol, the toxic compound found in the plants, the slightest contact can result in a painful itching rash.’
    • ‘These products often lay a polymer film on the skin that prevents urushiol from permeating to the dermal layer and, in so doing, function as a barrier.’
    • ‘Poison ivy, poison oak, and poison sumac all contain the same allergic irritant: urushiol.’
    • ‘All parts of the poison ivy plant produce the oily irritating agent, urushiol.’
    • ‘If you're lucky enough to learn of your child's contact with poison ivy within five to ten minutes, then there's a chance that you can wash off the urushiol oil, which causes the reaction.’
    • ‘Unfortunately, the study also found that carbon dioxide-enhanced poison ivy boasts a stronger strain of urushiol, which may prove even more poisonous to humans.’


Early 20th century: from Japanese urushi ‘Japanese lacquer’ + -ol.