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

• illuminational
  adjective
• nonillumination
  noun
• preillumination
  noun
• reillumination
  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

Actually, the fineness of the design is probably best appreciated at night, with its full plumage of illumination switched on.

From The Wall Street Journal • May 16, 2026

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

From BBC • Apr. 5, 2026

Additional lenses then organize the beams into a structured grid of square illumination areas at the receiving surface.

From Science Daily • Apr. 2, 2026

The Plaza features quaint Spanish village scenery built out of its side walls with background illumination that glows pink and then deep purple, emulating a setting sun as the lights go down.

From Los Angeles Times • Dec. 9, 2025

Two days later, Lincoln had made a speech proposing to give blacks the right to vote, and last night, April 13, all of Washington had celebrated with a grand illumination of the city.

From "Chasing Lincoln's Killer" by James L. Swanson

Related Words

• brightness