[ loo-muh-nuhns ]
/ ˈlu mə nəns /


the state or quality of being luminous.
Also called luminosity. the quality or condition of radiating or reflecting light: the blinding luminance of the sun.
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.



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Origin of luminance

1875–80; <Latin lūmin- (stem of lūmen) light + -ance Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for luminance

  • The remainder of the big room receded into a grey twilight encircling the patch of luminance.

    The Lamp of Fate|Margaret Pedler
  • A luminance seemed to come from above, from the unseen heights of the magnificent double staircase.

  • A few fluoros cast wan puddles of luminance on the plastic flooring.

    The Sensitive Man|Poul William Anderson

British Dictionary definitions for luminance

/ (ˈluːmɪnəns) /


a state or quality of radiating or reflecting light
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 directionSymbol: L

Word Origin for luminance

C19: from Latin lūmen light
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for luminance

[ lōōmə-nəns ]

The luminous intensity of a light source per unit area. Occasionally the lambert unit is used to measure luminance. Also called photometric brightness
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.