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

Lemon juice and fresh thyme add an earthy brightness to each bowl. —Jenna Sims, Southern Living, 7 Mar. 2026

This is because salt crystals can reflect sunlight efficiently, such deposits might have increased the planet’s overall brightness. —Rupendra Brahambhatt, Interesting Engineering, 7 Mar. 2026

Several automakers offer personalized lighting options, such as Ford’s MyColor and Mercedes-Benz’s 64-color LED lighting, which offers variable brightness, three lighting zones and 10 color moods. —Beth Livesay, AJC.com, 6 Mar. 2026

This was bad news, considering the rechargeable battery on this particular headlamp lasted a paltry 45 minutes at max brightness and 90 minutes at medium output, despite the brand’s grandiose promises. —Maggie Slepian, Outside, 6 Mar. 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