rainbow
n. countablen. a colorful arch that appears in the sky when it rains and the sun is shining. It is made of seven colors: red, orange, yellow, green, blue, indigo, and violet.
n. an arc of spectral colors appearing in the sky, caused by the refraction, reflection, and dispersion of light in water droplets. It typically manifests opposite the sun during rain.
A beautiful rainbow appeared in the sky after the storm.
The children ran outside to see the rainbow that stretched across the valley after the afternoon shower.
While a rainbow is often perceived as a semi-circle from the ground, an observer in an aircraft may occasionally witness a full circular phenomenon under the right atmospheric conditions.
From Middle English reynbowe, raynbowe, from Old English reġnboga (“rainbow”), from Proto-West Germanic regnabogō, from Proto-Germanic regnabugô (“rainbow”), equivalent to rain + bow (“arch”). Cognate with West Frisian reinbôge (“rainbow”), Dutch regenboog (“rainbow”), German Regenbogen (“rainbow”), Danish regnbue (“rainbow”), Swedish regnbåge (“rainbow”), Icelandic regnbogi (“rainbow”).
Commonly used with the verbs 'see', 'appear', or 'form'.