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

• brilliance
• brilliancy
• candor
• dazzle
• effulgence
• illumination
• lambency
• lightness
• luminance
• luminosity
• luminousness
• luster
• lustre
• lustrousness
• radiance
• refulgence
• splendor

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

On those nights, the moon will be at 40% brightness, which may interfere with viewing, according to the American Meteor Society. —Janet Loehrke, USA Today, 19 Apr. 2025

In our test, which involves playing a YouTube video on a loop with the screen at full brightness, the phone lasted 16 hours and 6 minutes on a single charge. —PC Magazine, 17 Apr. 2025

The lamp has a matte-gold finish, provides optimal brightness, and will look perfect on your work desk. —Nora Colomer, FOXNews.com, 17 Apr. 2025

Mango, lime, mint, and avocado add brightness and varied textures to the carrots ensuring every bite is full of flavor. —Alana Al-Hatlani, Southern Living, 16 Apr. 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