[ loo-muh-nuh ns ]
/ 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.

Nearby words

  1. lumen-hour,
  2. lumholtz's kangaroo,
  3. lumiere,
  4. luminaire,
  5. luminal,
  6. luminaria,
  7. luminary,
  8. luminate,
  9. lumine,
  10. luminesce

Origin of luminance

1875–80; < Latin lūmin- (stem of lūmen) light + -ance Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples 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

Word Origin and History for luminance



"luminousness," 1862, from Latin luminantem (nominative luminans), present participle of luminare (see luminary).

Online Etymology Dictionary, © 2010 Douglas Harper

Science 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.