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• rainbow
  rainbow

  noun

  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.
• Rainbow
  Rainbow

  noun

  a member of the Rainbow Guides, the youngest group of girls (aged 5-7 years) in The Guide Association

rainbow

American  

[reyn-boh] / ˈreɪnˌboʊ /

noun

• rainbows
  plural

1. 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.

2. a similar bow of colors, especially one appearing in the spray of a waterfall or fountain.

3. any brightly multicolored arrangement or display.

4. a wide variety or range; gamut.

5. a visionary goal.

   He pursued the rainbow of a singing career for years before becoming a success.

6. rainbow trout.

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adjective

1. having a diverse membership; including representatives from different races, ethnicities, genders, sexual orientations, etc.: LGBTQ Pride month celebrates all of the rainbow community.

   Archbishop Desmond Tutu famously described postapartheid South Africa as a rainbow nation.

   LGBTQ Pride month celebrates all of the rainbow community.

   Candidates are appealing to a rainbow coalition of minority voters.

rainbow ¹ British  

/ ˈreɪnˌbəʊ /

noun

1. 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

2. 1. any similar display of bright colours

   2. ( as modifier )

      a rainbow pattern

3. an illusory hope

   to chase rainbows

4. (modifier) of or relating to a political grouping together by several minorities, esp of different races

   the rainbow coalition

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Rainbow ² British  

/ ˈreɪnˌbəʊ /

noun

1. a member of the Rainbow Guides, the youngest group of girls (aged 5-7 years) in The Guide Association

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rainbow Scientific  

/ rān′bō′ /

1. An arc-shaped spectrum of color seen in the sky opposite the Sun, especially after rain, caused by the refraction and reflection of sunlight by droplets of water suspended in the air. Secondary rainbows that are larger and paler sometimes appear within the primary arc with the colors reversed (red being inside). These result from two reflections and refractions of a light ray inside a droplet.

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rainbow Cultural  

1. The colored arch in the sky that is often seen after a rain. The rainbow is formed when water droplets in the air cause the diffraction of sunlight.

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Discover More

The colors of the rainbow are violet, indigo, blue, green, yellow, orange, and red.

Other Word Forms

Derived Forms

• rainbowlike
  adjective
• rainbowy
  adjective

Inflected Forms

Nouns

• rainbows
  plural

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."

Example Sentences

See Examples For:

rainbow Rainbow rainbows

A microchip about the size of a grain of rice can generate a highly organized "rainbow" of light, a capability that could eventually support faster, higher-capacity 6G communications and extremely precise timing for quantum technologies.

From Science Daily ● Aug. 24, 2026

He is also expected to try to defend his Road World Championships rainbow jersey in Montreal, Canada, just a week after La Vuelta finishes.

From BBC ● Aug. 3, 2026

I like to follow through on my plans, so we headed to the Citadel outlets where we bought him rainbow sandals, dress shirts and black jeans.

From Los Angeles Times ● Jul. 31, 2026

Excursions with Vail Valley Anglers, booked through the hotel, offer a chance to cast for brown and rainbow trout.

From The Wall Street Journal ● Jul. 8, 2026

"Kabir," she asks me now, "remember what I told you about caterpillars bursting out of cocoons, all rainbow colored?"

From "Born Behind Bars" by Padma Venkatraman

A woman called Catherine Taylor Dawson, who ran in Cardiff North in 2005 for the Vote for Yourself Rainbow Dream Ticket party, won a single vote there, for instance.

From Slate ● Aug. 12, 2026

It was the first title released by Vantage Studios, a new subsidiary helming Ubisoft's top franchises including "Assassin's Creed", "Far Cry" and "Rainbow Six".

From Barron's ● Jul. 23, 2026

The BBC understands it was Forde's intervention in this argument off camera that led to the dispute with Rainbow minutes later.

From BBC ● Jul. 16, 2026

At a private reception for the show’s 50th anniversary at the Rainbow Room last year, Roberts presented Michaels with an antique watch made in 1975 with the SNL 50 logo painted on it.

From The Wall Street Journal ● Jul. 2, 2026

Rainbow flags waved on street corners around the country.

From "Becoming" by Michelle Obama

“There are storm clouds on the ground, but rainbows and sunshine in the air,” said Mark Coleman, chief commercial officer at Intervine, which helps wineries get their bottles on airlines like Delta and United.

From The Wall Street Journal ● Aug. 7, 2026

“This situation is clearly not all sunshine and rainbows, it’s cold and foggy.”

From MarketWatch ● Jul. 13, 2026

Soon his parents and older sister arrive from the air, trailing rainbows behind their colorful capes.

From Los Angeles Times ● Jan. 23, 2026

"This is not going to be the festival of rainbows and kisses as it was in the past," he told AFP.

From Barron's ● Dec. 17, 2025

A plain lunch box with no ponies or rainbows.

From "Wish" by Barbara O'Connor