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

This focuses the star’s light onto Earth like a lens of a giant magnifying glass, resulting in small increases in the brightness of stars as seen through telescopes. — Elijah Tan, Encyclopedia Britannica, 22 July 2026

If my face brings people a smile or some brightness in that very moment, that is a major achievement. — Dontaira Terrell, USA Today, 22 July 2026

Tender, lightly charred eggplant lends a silky texture and subtle smokiness that complements the couscous, while lemon juice, olive oil and a generous handful of fresh herbs infuse every bite with brightness. — Lynda Balslev, Mercury News, 21 July 2026

The more affordable Elfin Flip Laser provides 1080p resolution and similar brightness but lacks some advanced gaming features and optical zoom. — John Archer, Forbes.com, 21 July 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