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

The vibe inside the cabin can be controlled thanks to 128-color ambient RGB lighting and the vanity mirrors have 19 color-temperature options and 17 brightness levels. —New Atlas, 6 Dec. 2025

Mercury was still impossible to see through the brightness of dawn. —Joe Rao, Space.com, 4 Dec. 2025

Dolby's groundbreaking technology called Pulsar created a new level of brightness, detail, and color never seen before on a TV. —Mary Lee, CBS News, 4 Dec. 2025

Its Quantum Matrix Technology Plus brings adaptive brightness, and the 120Hz native refresh rate, combined with 165Hz VRR, makes gaming super smooth. —PC Magazine, 3 Dec. 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