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

While Russia has claimed GDP expanded by about 13% between 2020 and 2024, Sweden’s analysis of nighttime luminosity suggests the economy actually shrank by 8% during that span. —Jason Ma, Fortune, 24 May 2026

The magnificent luminosity of the orbs announced their arrival, their glow falling unfamiliar against windowpanes, which drew the people to the street. —Literary Hub, 20 May 2026

Four-Star Signiel Seoul’s retreat SIGNIEL Spa features advanced facials that incorporate targeted serums and ingredients like powdered diamond and pearls to refine the appearance of pores and enhance luminosity. —Melinda Sheckells, Forbes.com, 20 May 2026

In 2022, the United States had by far the highest total luminosity of any country, followed by China, India, Canada and Brazil. —Janet Loehrke, USA Today, 6 May 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