1. The act or practice of excluding.
2. The condition or fact of being excluded.
[Middle English exclusioun, from Latin exclūsiō, exclūsiōn-, from exclūsus, past participle of exclūdere, to shut; see EXCLUDE.]
ex·clusion·ar′y (-zhə-nĕr′ē) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.