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

New color, brightness, and glare control Image quality remains a core focus of LG’s premium strategy. —Sujita Sinha, Interesting Engineering, 5 Jan. 2026

Yellow If some of your rooms don't experience much natural sunlight, consider a paint color that can help boost the brightness. —Nashia Baker, Martha Stewart, 4 Jan. 2026

Betelgeuse fluctuates in diameter and brightness. —Mike Lynch, Twin Cities, 4 Jan. 2026

Choose from three brightness modes (soft, bright, and super bright), three light modes (breathing, flashing, and constant), and four timing controls (two, four, six, and eight hours). —Quincy Bulin, Better Homes & Gardens, 4 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