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 team expects the mysterious object to once again impact the brightness of the star in between 42 and 43 years. —Robert Lea, Space.com, 13 Feb. 2026

These systems optimize contrast, brightness, and color with machine learning algorithms that adjust to scene content and ambient light, significantly enhancing viewing quality without manual calibration. —Jason Phillips, USA Today, 11 Feb. 2026

At massive audiovisual conferences like ISE 2026, extreme projection is everywhere, from the large venues and expansive screens to immersive installations and rental setups built around impressive brightness. —New Atlas, 11 Feb. 2026

Giving the camera longer exposure increases brightness but may reduce definition if the aurora is active. —Lydia Price, Travel + Leisure, 10 Feb. 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