noun, plural lu·mi·nos·i·ties.

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 formsnon·lu·mi·nos·i·ty, nounself-lu·mi·nos·i·ty, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for luminosity

light, glow, brightness, luminance, fluorescence

Examples from the Web for luminosity

Contemporary Examples of luminosity

Historical Examples of luminosity

  • 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.

  • He nodded toward the circular area of luminosity on the sea.

    Creatures of the Abyss

    Murray Leinster

British Dictionary definitions for luminosity


noun plural -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 observedFormer 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

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