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il·lu·mi·nate (ĭ-lmə-nāt)
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tr.v. il·lu·mi·nat·ed, il·lu·mi·nat·ing, il·lu·mi·nates
1. To provide or brighten with light.
2. To decorate or hang with lights.
3.
a. To make understandable; clarify: "Cleverly made attacks can ... serve to illuminate important differences between candidates" (New Republic).
b. To enlighten intellectually or spiritually; enable to understand: "I greatly misdoubt the accuracy of this ... Can you illuminate me?" (Charles Darwin).
4. To adorn (a page of a book, for example) with ornamental designs, images, or lettering in brilliant colors or precious metals.
5. To expose to or reveal by radiation.
n. (-nĭt)
One who has or professes to have an unusual degree of enlightenment.

[Middle English illuminaten, from Latin illūmināre, illūmināt- : in-, in; see IN-2 + lūmināre, to light up (from lūmen, lūmin-, light; see leuk- in the Appendix of Indo-European roots).]

il·lumi·nating·ly adv.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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:

    Indo-European Roots

    Semitic Roots

    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.