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

• 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

Henderson used sconces and a bold chandelier from Blueprint Lighting not merely for brightness, but as sculptural statements throughout the house. —Kathy Barnes, Better Homes & Gardens, 4 Oct. 2025

Why White Towels Lose Their Brightness There are many reasons why white towels might lose their brightness over time. —Daley Quinn, Southern Living, 4 Oct. 2025

Remember, magnitude is the scale used by astronomers to chart the apparent brightness of an object in the night sky. —Anthony Wood, Space.com, 3 Oct. 2025

The way the plume spread and its lasting brightness indicate a high altitude above 100 km (62 miles), typical for medium- to intercontinental-range missile tests. —Kapil Kajal, Interesting Engineering, 1 Oct. 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