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

Typical brightness is 1,000 nits, with a peak of 1,600 nits, and an outdoor peak of 3,000 nits. — Eric Zeman, PC Magazine, 21 Oct. 2026

Aside from its brightness, everything else about the BOAT fits the model of a typical long-duration GRB. — Robin George Andrews, Scientific American, 20 Oct. 2026

In Pommes d’Api, which is owned by the Minneapolis Institute of Art and was too fragile to bring to Paris, the brightness of Gonzalès’s reds and yellows convey the apples’ acidity. — Sarah Belmont, ARTnews.com, 19 Oct. 2026

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

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