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[loo-muh-nos-i-tee] /ˌlu məˈnɒs ɪ ti/
noun, plural luminosities.
luminance (def 2).
the quality of being intellectually brilliant, enlightened, inspired, etc.:
The luminosity of his poetry is unequaled.
something luminous.
Astronomy. the brightness of a star in comparison with that of the sun: the luminosity of Sirius expressed as 23 indicates an intrinsic brightness 23 times as great as that of the sun.
Also called luminosity factor. Optics. the brightness of a light source of a certain wavelength as it appears to the eye, measured as the ratio of luminous flux to radiant flux at that wavelength.
Origin of luminosity
1625-35; < Latin lūminōs(us) luminous + -ity
Related forms
nonluminosity, noun
self-luminosity, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for luminosity
Contemporary Examples
Historical Examples
  • It is the radiations of light which they throw off; it is their luminosity—their transparency.

  • There was luminosity where the ships had encountered each other.

    The Aliens Murray Leinster
  • Value or luminosity of colors ranges between these two extremes.

    A Color Notation Albert H. Munsell
  • But this luminosity is not entirely confined to the minute creatures of the sea.

    The Ocean and its Wonders R.M. Ballantyne
  • He nodded toward the circular area of luminosity on the sea.

    Creatures of the Abyss Murray Leinster
  • Now the mist about him took on a luminosity which was of a different kind.

    Nightmare Planet Murray Leinster
  • Abnormal darkness,” it was added, “follows as a reaction after luminosity.

  • If we need a noun we say "luminosity," which is abstract, being derived from an adjective.

    Instigations Ezra Pound
  • We have been shooting like a meteor as to rapidity, but without its luminosity.

    Speeches of Benjamin Harrison Benjamin Harrison
British Dictionary definitions for luminosity


noun (pl) -ties
the condition of being luminous
something that is luminous
(astronomy) a measure of the radiant power emitted by a star
(physics) the attribute of an object or colour enabling the extent to which an object emits light to be observed Former name brightness See also colour
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
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Word Origin and History for luminosity

1630s, "quality of being luminous," from French luminosité or else a native formation from luminous + -ity. In astronomy, "intrinsic brightness of a heavenly body" (as distinguished from apparent magnitude, which diminishes with distance), attested from 1906.

Online Etymology Dictionary, © 2010 Douglas Harper
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