Definition of poison oak
1 : any of several plants related to poison ivy and producing an oil with similar irritating properties: such as
a : a bushy plant (Toxicodendron diversilobum synonym Rhus diversiloba) of the Pacific coast
b : a bushy plant (Toxicodendron toxicarium synonym Rhus toxicodendron) chiefly of the southeastern U.S.
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
Ask the Editors