v. ir·ra·di·at·ed, ir·ra·di·at·ing, ir·ra·di·ates
a. To expose to radiation.
b. To treat with radiation: irradiate farm produce so as to destroy bacteria.
2. To shed light on; illuminate.
3. To manifest in a manner suggesting the emission of light; radiate: irradiate goodness.
1. To send forth rays; radiate.
2. To become radiant.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.