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

• 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

The brightness and color reproduction are lackluster, almost as if Acer deliberately found the most middling budget screen possible. —PC Magazine, 27 June 2025

The display is configurable with nine different color schemes, adjustable brightness and more. —Mark Sparrow, Forbes.com, 27 June 2025

To qualify as a bolide, an incoming meteor must reach the brightness of Venus, which, like the moon, is often visible in the daytime sky. —Jeffrey Kluger, Time, 27 June 2025

Experts in the the Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS) project captured this image, using a special coronagraph imager, which allows cameras to see beyond the brightness of a star. —Kenna Hughes-Castleberry, Space.com, 23 June 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