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 of luminosity

• 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

Inspired by the traditional Korean beauty ritual of rice-water cleansing, this shampoo focuses on boosting natural luminosity and deep hydration. —Iman Balagam, Vogue, 27 Apr. 2026

Even more surprising, the nebula’s gamma-ray luminosity at PeV energies is several times higher than that of the Crab Nebula, despite its weaker pulsar. —Rupendra Brahambhatt, Interesting Engineering, 26 Apr. 2026

What sets the temperature and luminosity of a star? —Big Think, 24 Apr. 2026

Arriving in a jet-black shade, this wig possesses a luminosity that almost seems artificial. —Noel Cymone Walker, StyleCaster, 1 Apr. 2026

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