illumination

American  

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

noun

1. an act or instance of illuminating. 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”; illuminate ( def. ), -ion ( def. )

Example Sentences

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

Lighting design by Manuel Da Silva, the group’s production manager, provided pools and shafts of illumination to dramatize the darkened stage.

From The Wall Street Journal • Jan. 20, 2026

When the sun vanishes early and the chill of darkness comes on deep and fast, there has always been an instinct to gather around a source of warmth and illumination for tales of fearsome happenings.

From Los Angeles Times • Dec. 23, 2025

Over time, that illumination can also alter the fluorescent molecules themselves so they no longer emit enough light, a problem known as photobleaching that limits how long experiments can run.

From Science Daily • Dec. 19, 2025

The sand was grayish blue, though the weird illumination made it difficult to judge its true color.

From "City of the Plague God" by Sarwat Chadda

Related Words

• brightness