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brightness

American  
[brahyt-nis] / ˈbraɪt nɪs /

noun

  1. the quality of being bright.

  2. Optics. the luminance of a body, apart from its hue or saturation, that an observer uses to determine the comparative luminance of another body. Pure white has the maximum brightness, and pure black the minimum brightness.

brightness British  
/ ˈbraɪtnɪs /

noun

  1. the condition of being bright

  2. physics a former name for luminosity

  3. psychol the experienced intensity of light

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of brightness

before 950; Middle English brihtnes, Old English beorhtnes. See bright, -ness

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Cook them until they yield slightly but retain their brightness.

From Salon • Apr. 7, 2026

The depth comes from the butter and tomato, the brightness from the finish.

From Salon • Apr. 3, 2026

There was a grace about her, an untroubled brightness.

From Slate • Mar. 29, 2026

But there is a palpable brightness in her voice when I ask about her son, Teo, whose name we have changed.

From BBC • Mar. 13, 2026

The same logic works in reverse; if you know how much light a train’s headlight emits, you can measure its apparent brightness and calculate the train’s distance from you.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.