luminosity

noun

lu·​mi·​nos·​i·​ty ˌlü-mə-ˈnä-sə-tē 

plural luminosities

1

a

: the quality or state of being luminous

b

: something luminous

2

a

: 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)

Synonyms

• brightness
• brilliancy
• brilliance
• lightness

Examples of luminosity in a Sentence

the luminosity of the fireflies made for an enchanting nighttime show

Recent Examples on the Web

The energy and luminosity of an ENT boggles the mind. —Andrew Paul, Popular Science, 4 June 2025

This freedom of expression lends every canvas with a luminosity and energy that leaves a lasting impression. —Lee Sharrock, Forbes.com, 23 May 2025

Surgeons routinely incorporate lasers and peels into facelifts to treat sun damage and restore luminosity for a time. —Jolene Edgar, Allure, 10 June 2025

Stars burn like celestial nuclear fusion reactors, quasars emit thousands of times the luminosity of the Milky Way galaxy, and asteroids slam into planets. —Andrew Paul, Popular Science, 4 June 2025

Word History

Etymology

borrowed from Middle French & Medieval Latin; Middle French luminosité, borrowed from Medieval Latin lūminōsitāt-, lūminōsitās, from Latin lūminōsus "full of light, luminous" + -itāt-, -itās -ity

First Known Use

1634, in the meaning defined at sense 1a

Rhymes for luminosity

• adiposity

Kids Definition

luminosity

noun

lu·​mi·​nos·​i·​ty ˌlü-mə-ˈnäs-ət-ē 

plural luminosities

1

: the quality or state of being luminous : brightness

2

: something luminous

Medical Definition

luminosity

noun

lu·​mi·​nos·​i·​ty ˌlü-mə-ˈnäs-ət-ē 

plural luminosities

1

: the quality or state of being luminous

2

a

: the relative quantity of light

b

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