rainbow

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."

Definitions of rainbow
1

n an arc of colored light in the sky caused by refraction of the sun's rays by rain

Type of:
arc, bow
something curved in shape

n an illusory hope

“chasing rainbows
Type of:
hope, promise
grounds for feeling hopeful about the future

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