illuminance

[ ih-loo-muh-nuhns ]

noun

, Optics.

1. illumination ( def 6 ).

illuminance

/ ɪˈluːmɪnəns /

noun

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

illuminance

/ 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

Word History and Origins

Origin of illuminance¹

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

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

From Washington Post

“The results thus show that modifying the ambient illuminance level in a restaurant does not only affect the overall ambiance but also changes the overall taste experience of the food being served.”

From Fox News

The user of this tool, however, will encounter terms like “macular pigment optical density,” “vertical photopic illuminance” and “spectral power distribution,” indicators that it’s probably best left to professional lighting designers.

From New York Times