illumination

American  

[ih-loo-muh-ney-shuhn] / ɪˌlu məˈneɪ ʃən /

noun

1. an act or instance of illuminating.

2. the fact or condition of being illuminated.

3. a decoration of lights, usually colored lights.

4. Sometimes illuminations. an entertainment, display, or celebration using lights as a major feature or decoration.

5. intellectual or spiritual enlightenment.

   Synonyms:

   wisdom, insight, revelation, knowledge

6. Also called illuminance.  Also called intensity of illumination.  Optics. the intensity of light falling at a given place on a lighted surface; the luminous flux incident per unit area, expressed in lumens per unit of area.

7. a supply of light.

   a source of illumination.

8. decoration of a manuscript or book with a painted design in color, gold, etc.

9. a design used in such decoration.

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illumination British  

/ ɪˌluːmɪˈneɪʃən /

noun

1. the act of illuminating or the state of being illuminated

2. a source of light

3. (often plural) a light or lights, esp coloured lights, used as decoration in streets, parks, etc

4. spiritual or intellectual enlightenment; insight or understanding

5. the act of making understood; clarification

6. decoration in colours, gold, or silver used on some manuscripts or printed works

7. physics another name (not in technical usage) for illuminance

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Other Word Forms

Derived Forms

• reillumination
  noun
• illuminational
  adjective
• preillumination
  noun
• nonillumination
  noun

Etymology

Origin of illumination

First recorded in 1300–50; Middle English, from Medieval Latin illūminātiōn-, stem of illūminātiō “spiritual enlightenment,” from Latin: “illustriousness, glory”; see illuminate ( def. ), -ion ( def. )

Explanation

Illumination is light. Kids up past their bedtimes have been known to read entire books under their covers using only the illumination from a flashlight. Use the noun illumination to talk about light, like the illumination of the moon on the surface of a lake. Illumination can also refer to an understanding or a spiritual awareness, like when a mystery of your faith suddenly makes sense to you. The Latin root is illuminationem, "throw into light" — you can picture the light bulb over a person's head in a cartoon to remember the various meaning of illumination.

Example Sentences

The telescope would allow wide area observations of the lunar surface during strong solar flares, when the Sun provides more intense X-ray illumination.

From Science Daily • Jun. 6, 2026

Even Apollo astronauts didn't see the Orientale basin completely because of their orbit and illumination conditions.

From BBC • Apr. 5, 2026

By simply changing the level of illumination, they could prompt particles to assemble into crystals or break apart again.

From Science Daily • Mar. 2, 2026

L.A. and its music scenes tend to be fervently, rigorously casual — daylight blinds the spotlight as the preferred illumination for concerts and parties.

From Los Angeles Times • Jan. 28, 2026

He no longer tried to fight, but acted stunned as if for the first time there was some illumination, some comprehension of the enormity of the resistance in a once placid kingdom.

From "The Great Santini" by Pat Conroy

Related Words

• brightness