luminosity
Americannoun
plural
luminosities-
the quality of being intellectually brilliant, enlightened, inspired, etc..
The luminosity of his poetry is unequaled.
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something luminous.
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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.
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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.
noun
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the condition of being luminous
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something that is luminous
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astronomy a measure of the radiant power emitted by a star
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Former name: brightness. physics the attribute of an object or colour enabling the extent to which an object emits light to be observed See also colour
Other Word Forms
Etymology
Origin of luminosity
Explanation
Luminosity is the quality of something that gives off light or shines with reflected light. The most noticeable quality of a large, sparkly diamond is its luminosity. You might describe a bright and lively oil painting in terms of its luminosity, or marvel at the luminosity of a brilliant sunset. Astronomers use the word luminosity to talk about a specific property of physics, the energy given of by an astronomical object in a certain amount of time. There's a direct correlation between this amount of energy and the object's brightness. The Latin root is lumen, meaning "light."
Vocabulary lists containing luminosity
Space Science
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The ACT Science Test: Space Science Review
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Space Science Review
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
He aptly describes the projectors’ beams of luminosity as “light sculptures.”
From Los Angeles Times • Feb. 23, 2026
Moreover, the luminosity changed by more than two orders of magnitude in about 10 years.
From Science Daily • Dec. 14, 2025
“I have no medium that can give me color of such wonderful luminosity as the Autochrome plate,” wrote the photographer Edward Steichen in 1908.
From The Wall Street Journal • Nov. 21, 2025
She found a relationship between their variation period, or pulse, and their intrinsic brightness or luminosity.
From Salon • Feb. 14, 2025
Even the greens, her favorite shades of greens, flee the trees and assault her with luminosity.
From "Dreaming in Cuban" by Cristina García
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
