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 hotter and bluer white dwarfs are mostly brighter, so they can be seen from further away and are over-represented in surveys that only look at a star’s brightness. — Laura Baisas, Popular Science, 15 Oct. 2026

Features such as adaptive brightness, low blue light technology and ergonomic adjustability can help create a more comfortable experience while preserving the visual quality users expect. — George Toh, Forbes.com, 13 Oct. 2026

Niacinamide is also included to gradually enhance skin brightness of any post-breakout dark spots. — Conçetta Ciarlo, Vogue, 13 Oct. 2026

Lasting less than 60 days and consisting of two 5-day blasts, this episode saw a doubling of the X-ray brightness of the AGN at the heart of NGC 1275. — Robert Lea, Space.com, 12 Oct. 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