brightness

noun

bright·​ness ˈbrīt-nəs 

1

a

: the quality or state of being bright

also : an instance of such a quality or state

b

: luminance

2

: the attribute of light-source colors by which emitted light is ordered continuously from light to dark in correlation with its intensity compare hue sense 2c, lightness entry 1 sense 2a, saturation sense 4

Synonyms of brightness

• brilliancy
• brilliance
• lightness
• illumination
• luminosity

Examples of brightness in a Sentence

the brightness of the sunshine made me squint after an afternoon spent in a darkened movie theater

Recent Examples on the Web

Why the dead girl’s computer glows with an unnatural brightness whenever the lights turn off? — David Ehrlich, IndieWire, 10 Sep. 2026

Additionally, SnV centers emit light at roughly 10 times the brightness of NV centers. — Georgina Jedikovska, Interesting Engineering, 8 Sep. 2026

Two physical irises work in sequence to regulate the light path, one of which adjusts dynamically based on the scene brightness. — New Atlas, 8 Sep. 2026

The essential oils on top of the martini give an extra brightness. — The Editors, Robb Report, 7 Sep. 2026

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1a

Rhymes for brightness

• lightness
• rightness
• tightness
• whiteness
• finiteness
• politeness
• uprightness

Medical Definition

brightness

noun

bright·​ness ˈbrīt-nəs 

: the one of the three psychological dimensions of color perception by which visual stimuli are ordered continuously from light to dark and which is correlated with light intensity compare hue, saturation sense 4a