urushiol

u·ru·shi·ol   (ŏŏ-rōō'shē-ôl', -ōl', -ŏl')    n.  A toxic substance present in the resin or on the surface of plants of the genus Rhus, including poison ivy and the lacquer tree, from which a black Japanese lacquer is obtained. [Japanese urushi, lacquer + -ol1.]

Main Entry: uru·shi·ol
Pronunciation: (y)u-'rü-shE-"ol, -"Ol
Function: noun
: a mixture of pyrocatechol derivatives with saturated orunsaturated side chains of 15 or 17 carbon atoms that is an oily toxic irritant principle present in poison ivy and some related plants of the genus Rhus

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

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.