1. A North American shrub or vine (Toxicodendron radicans) that has compound leaves with three leaflets, small green flowers, and whitish berries and that causes a rash on contact.
2. A skin rash caused by contact with this plant. In both senses also called poison oak.
(click for a larger image)poison ivy
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.