illuminance

American  

[ih-loo-muh-nuhns] / ɪˈlu mə nəns /

noun

Optics.

1. illumination.

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illuminance British  

/ ɪˈluːmɪnəns /

noun

1.  Ev.  Sometimes called: illumination.  the luminous flux incident on unit area of a surface. It is measured in lux Compare irradiance

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illuminance Scientific  

/ ĭ-lo̅o̅′mə-nəns /

1. The luminous flux per unit area at any point on a surface exposed to incident light. It is measured in luxes.

2. Also called illumination

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Etymology

Origin of illuminance

First recorded in 1940–45; illumin(ate) + -ance

Example Sentences

“Rather than starting with light levels, illuminance requirements, energy codes or the like,” Mr. Brandston advised, “ask yourself: ‘What do you wish to see?’”

From New York Times • Mar. 24, 2023

It’s also tough to tell if the light in the back is sunlight or illuminance from the lightning.

From Washington Post