lu·​mi·​nos·​i·​ty | \ˌlü-mə-ˈnä-sə-tē \
plural luminosities

Definition of luminosity 

1a : the quality or state of being luminous

b : something luminous

2a : the relative quantity of light

b : relative brightness of something

3 : the relative quantity of radiation emitted by a celestial source (such as a star)

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Examples of luminosity in a Sentence

the luminosity of the fireflies made for an enchanting nighttime show

Recent Examples on the Web

In part, that’s because the new Spectre x360 uses a 1-watt display panel that still manages to pump out a maximum of 400 nits of luminosity. Mark Hachman, PCWorld, "HP Spectre x360 13 (2018) hands on: 'Whiskey Lake' power sits alongside 22 hours of battery life," 23 Oct. 2018 The event, named ASASSN-15lh, was originally classified as the brightest supernova ever observed, with a luminosity reaching 50 times the brightness of the entire Milky Way. Jay Bennett, Popular Mechanics, ""Brightest Supernova Ever" Turns Out to Be a Star Ripped Apart by a Supermassive Black Hole," 12 Dec. 2016 The beautiful face duos are available in both cream and powder formulas, each including a blush and illuminator that complement each other and boost your face's luminosity and glow. Tynan Sinks, Allure, "The Best Natural and Organic Makeup Brands That Makeup Artists Actually Use," 6 June 2018 Everything claims to enhance radiance and luminosity. Kathleen Hou, The Cut, "A Celebrity Dermatologist’s Science-Based Skin-Care Routine," 12 July 2018 To create its galactic map, the spacecraft tracks the positions, motions and luminosities of more than a billion stars, providing full three-dimensional trajectories for many of them. Shannon Hall, Scientific American, "The Milky Way's Speediest Stars Could Solve a 50-Year-Old Mystery," 9 May 2018 Enhance your inner glow Everyone is obsessed with adding a luminosity to their makeup this summer, so why not mix it into your sunscreen routine? Andrea Mandell, USA TODAY, "5 SPF trends your face needs this summer," 29 June 2018 The blue painting came from an exercise in creating depth through perspective, shadow, and luminosity. Aaron Gilbreath, Longreads, "Old In Art School," 20 June 2018 The luminosity of Christina Pecce’s soprano seems right for the otherworldly Helen; her wordless melismas at the very end are particularly effective. John Von Rhein,, "Chicago Fringe Opera's bare-bones staging of 'Great God Pan' brings more spills than chills," 15 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'luminosity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of luminosity

1634, in the meaning defined at sense 1a

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20 Nov 2018

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The first known use of luminosity was in 1634

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More Definitions for luminosity


lu·​mi·​nos·​i·​ty | \ˌlü-mə-ˈnäs-ət-ē \
plural luminosities

Medical Definition of luminosity 

1 : the quality or state of being luminous

2a : the relative quantity of light

b : the comparative degree to which light of a given wavelength induces the sensation of brightness when perceived

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