rainbow
Americannoun
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a bow or arc of prismatic colors appearing in the heavens opposite the sun and caused by the refraction and reflection of the sun's rays in drops of rain.
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a similar bow of colors, especially one appearing in the spray of a waterfall or fountain.
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any brightly multicolored arrangement or display.
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a wide variety or range; gamut.
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a visionary goal.
He pursued the rainbow of a singing career for years before becoming a success.
adjective
noun
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a bow-shaped display in the sky of the colours of the spectrum, caused by the refraction and reflection of the sun's rays through rain or mist
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any similar display of bright colours
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( as modifier )
a rainbow pattern
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an illusory hope
to chase rainbows
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(modifier) of or relating to a political grouping together by several minorities, esp of different races
the rainbow coalition
noun
Discover More
The colors of the rainbow are violet, indigo, blue, green, yellow, orange, and red.
Other Word Forms
Etymology
Origin of rainbow
First recorded before 1000; Middle English reinbowe, Old English regnboga, rēnboga; cognate with Old Norse regnbogi, German Regenbogen; see rain, bow 2
Explanation
That colorful arc you sometimes see in the sky right after it stops raining? That's a rainbow. The scientific explanation for a rainbow's appearance is that light is refracted in water droplets, briefly revealing the full visible spectrum of light — all of the colors that make it up. While there are actually about a hundred colors in the visible spectrum, we tend to describe a rainbow as having six or seven. In Old English, there were two words for this phenomenon: scurboga, or "shower-bow," proved to be less popular than renboga, "rain bow."
Vocabulary lists containing rainbow
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 129-foot waterfall — a wide curtain of white water cascading from a basalt cliff face — generates its own rainbow and once was dubbed the “Eighth Wonder of the World” by President Theodore Roosevelt.
From Los Angeles Times • May 5, 2026
This process creates a spectrum, which is similar to a rainbow that reveals how light is distributed across different wavelengths.
From Science Daily • May 5, 2026
The scene in the rainbow picture is late afternoon in haying season, probably July.
From The Wall Street Journal • May 1, 2026
If you want to wear rainbow chard, a sardine tin, or a TV dinner in your hair, Lennick has a clip for that, though the company's bestseller is a strawberry.
From BBC • Apr. 22, 2026
A rainbow trail emerged and shot straight into the sky.
From "Healer of the Water Monster" by Brian Young
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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.