color index
Americannoun
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the difference between the apparent photographic magnitude and the apparent visual magnitude of a star.
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the difference between the magnitudes of a star in any two spectral regions.
Etymology
Origin of color index
First recorded in 1920–25
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.
The color index and how the eye and film “see” colors are discussed.
From Textbooks ● Oct. 13, 2016
A color index of a star is the difference in the magnitudes measured at any two wavelengths and is one way that astronomers measure and express the temperature of stars.
From Textbooks ● Oct. 13, 2016
Why use a color index if it ultimately implies temperature?
From Textbooks ● Oct. 13, 2016
A color index might lead reporters with an appetite for eye-catching headlines to produce misleading stories of an out-of-control border.
From Washington Times ● Apr. 22, 2016
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.
