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

This brightness is anchored by the deep earthy bitterness of the Cynar, the Japanese Whiskey offers a soft grain finish, and the salt keeps the whole project from becoming too bitter. —Jeremy Repanich, Robb Report, 25 Oct. 2025

Essentially the second tone knob engages an onboard distortion circuit, and when it's activated, a rendering of Godzilla on the pickguard glows and pulsates, the brightness varying depending on the gain levels. —New Atlas, 24 Oct. 2025

On the 100th anniversary of the ball drop in 2007, the lightbulbs were replaced with LED technology, dramatically increasing the brightness and range of colors on the ball. —Desiree Anello, PEOPLE, 23 Oct. 2025

Scientists measure the planet’s brightness by factoring in how much light reaches earth and how much is reflected back out to space (as measured by orbiting satellites). —Ryan Green, Scientific American, 22 Oct. 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