luminance
Americannoun
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the state or quality of being luminous.
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Also called luminosity. the quality or condition of radiating or reflecting light.
the blinding luminance of the sun.
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Optics. the quantitative measure of brightness of a light source or an illuminated surface, equal to luminous flux per unit solid angle emitted per unit projected area of the source or surface.
noun
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a state or quality of radiating or reflecting light
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L. a measure (in candelas per square metre) of the brightness of a point on a surface that is radiating or reflecting light. It is the luminous intensity in a given direction of a small element of surface area divided by the orthogonal projection of this area onto a plane at right angles to the direction
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The luminous intensity of a light source per unit area. Occasionally the lambert unit is used to measure luminance.
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Also called photometric brightness
Etymology
Origin of luminance
1875–80; < Latin lūmin- (stem of lūmen ) light + -ance
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The study drew a link between higher levels of luminance - meaning the intensity of light - and the likelihood of experiencing glare.
From BBC • Feb. 18, 2026
The Perseid meteor shower is back for its annual display, dotting our skies with its signature bright, streaking trails at peak luminance.
From Salon • Aug. 9, 2024
Early in life, when newborns receive strongly limited color information, the brain is forced to learn to distinguish objects based on their luminance, or intensity of light they emit, rather than their color.
From Science Daily • May 23, 2024
But at dawn and dusk, when males of the species swoop and dart in the pale luminance to attract a mate, they really shine.
From Science Magazine • Dec. 21, 2022
Near the central star there may be a retinue of dead worlds, the remnants of planets once full of life and now airless and ocean-free, bathed in a wraithlike luminance.
From "Cosmos" by Carl Sagan
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.