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

Here are six attractions — some on foot and others by car — that will bring brightness and warmth. —Domenica Bongiovanni, IndyStar, 21 Nov. 2025

Rather than studying it spectroscopically, the team used years of data about the star’s fluctuating brightness from NASA’s Transiting Exoplanet Survey Satellite. —Phil Plait, Scientific American, 20 Nov. 2025

Its display is covered by an anti-reflective coating, which, when combined with its brightness, should make the screen easy to see even under bright lighting conditions. —PC Magazine, 19 Nov. 2025

Orange and cranberry bread pudding is a cozy Southern classic that combines the tangy brightness of citrus with the tart sweetness of cranberries, soaked into rich, custard-like bread. —Aly Walansky, Southern Living, 18 Nov. 2025

Word History

First Known Use

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

Rhymes for brightness

• lightness
• rightness
• tightness
• whiteness
• 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