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colour index

British  

noun

  1. astronomy the difference between the apparent magnitude of a star measured in one standard waveband and in a longer standard waveband, indicating its colour and temperature

  2. geology the sum of the dark or coloured minerals of a rock, expressed as a percentage of the total minerals

  3. chem physics a systematic arrangement of colours according to their hue, saturation, and brightness

"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

Example Sentences

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“Cheaper LEDs will have a lower colour index of about 80, whereas daylight is about 100,” says Storey.

From The Guardian • Nov. 10, 2020

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.