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

Future Amazon Leo satellites are expected to orbit at lower altitudes of around 366 miles (590 km), which will further increase their brightness. —Tereza Pultarova, Space.com, 25 Jan. 2026

The film takes place in a dreary town in Victoria, Australia, a drab industrial backwater whose people — or, at least some of whom — flock to religion to give their lives the brightness of hope and higher purpose. —Richard Lawson, HollywoodReporter, 24 Jan. 2026

The shape and brightness of the rekindled tail trace the complex interactions that occurred between the AGN’s ejected jet and the ICM as the jet propagated outward. —K. R. Callaway, Scientific American, 24 Jan. 2026

To conserve your cellphone battery, lower screen brightness, close unused apps and text instead of call when possible. —Alex Perry, Cincinnati Enquirer, 23 Jan. 2026

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