A woody vine plant in the family Anacardiaceae (Toxicodendron radicans or Rhus toxicodendron), well-known for its ability to produce urushiol, a skin irritant that causes an itching rash for most people.

Any of three ivy-like species of Toxicodendron, known for their ability to cause an itching rash and blistering for most people, through urushiol, an oil that is a skin irritant.

plural of poison ivy

Toxicodendron radicans, the ivy-like species of Toxicodendron, common in the eastern United States, known for its ability to cause an itching rash and blistering for most people, through urushiol.

Toxicodendron rydbergii, an ivy-like species of Toxicodendron common in the western United States, well-known for its ability to causes an itching rash and blistering for most people, through urushiol, an oil that is a skin irritant.