illuminate

American  

[ih-loo-muh-neyt, ih-loo-muh-nit, -neyt] / ɪˈlu məˌneɪt, ɪˈlu mə nɪt, -ˌneɪt /

verb (used with object)

illuminated, illuminating

1. to supply or brighten with light; light up.

2. to make lucid or clear; throw light on (a subject).

   Synonyms:

   elucidate, explain, clarify

3. to decorate with lights, as in celebration.

4. to enlighten, as with knowledge.

5. to make resplendent or illustrious.

   A smile illuminated her face.

6. to decorate (a manuscript, book, etc.) with colors and gold or silver, as was often done in the Middle Ages.

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verb (used without object)

illuminated, illuminating

1. to display lights, as in celebration.

2. to become illuminated.

adjective

1. Archaic. illuminated.

2. Obsolete. enlightened.

noun

1. Archaic. a person who is or affects to be specially enlightened.

illuminate British  

verb

1. (tr) to throw light in or into; light up

   to illuminate a room

2. (tr) to make easily understood; clarify

3. to adorn, decorate, or be decorated with lights

4. (tr) to decorate (a letter, page, etc) by the application of colours, gold, or silver

5. (intr) to become lighted up

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adjective

1. archaic made clear or bright with light; illuminated

noun

1. a person who has or claims to have special enlightenment

Other Word Forms

• illuminatingly adverb
• illuminative adjective
• illuminator noun
• preilluminate verb (used with object)
• reilluminate verb
• semi-illuminated adjective
• unilluminated adjective

Etymology

Origin of illuminate

First recorded in 1400–50; late Middle English, from Latin illūminātus, past participle of illūmināre “to light up, brighten”; illumine ( def. ), -ate ¹ ( def. )

Explanation

To illuminate is to light up — with physical light or with an idea. A spotlight might illuminate an actor on stage, and a good chemistry teacher might illuminate students with a lesson on the atomic structure of hydrogen. Originally, the verb illuminate referred to decorating handwritten manuscripts with bright lettering or pictures. Monks illuminated manuscripts with colors like gold, silver, bright red, and blue. Nowadays you can illuminate anything in the dark — either literally or figuratively. If you are afraid of the dark, illuminate your bedroom. In the dark when it comes to organic chemistry? Get an illuminating tutor.

Example Sentences

They used the drone to illuminate the site and transmit video to colleagues so they could see the diver was safe.

From The Wall Street Journal • Feb. 15, 2026

The streetlights illuminate what looks like fog, and you can see little particles of dust and debris swirling around.

From Slate • Feb. 12, 2026

No floodlights illuminate the night sky when the citizens of Mexico’s Gotham need a hand.

From Los Angeles Times • Jan. 20, 2026

The “Cold Mountain” gaffe was a rare instance of a “Good Hang” research flub, one that inadvertently managed to illuminate more of Paltrow’s self-perception.

From Salon • Jan. 16, 2026

“Keep to that,” Jones instructs Booth, lighting a small candle to illuminate Booth’s compass and pointing to the southwesterly heading.

From "Lincoln's Last Days: The Shocking Assassination that Changed America Forever" by Bill O'Reilly

Related Words

• clarify
• define
• dramatize
• elucidate
• explain
• illustrate