What does rainbow mean?
A rainbow is the coloured arc that can appear in the sky when sunlight passes through raindrops. The light bends, reflects inside each drop, and separates into its component colours, creating the familiar band of red, orange, yellow, green, blue, indigo, and violet. The word also has metaphorical uses: a “rainbow of” colours or opinions means a wide and varied selection. Rainbows are strongly associated with beauty, hope, good fortune, and LGBTQ+ pride, and the expression “at the end of the rainbow” refers to a hoped-for place or reward that may be difficult or impossible to find. In general, “rainbow” combines a precise physical meaning with a broad symbolic vocabulary of diversity and possibility.
A curved band of coloured light seen in the sky when sunlight is refracted and dispersed by raindrops.
"A faint rainbow stretched across the wet field."
Usually singular when referring to one atmospheric phenomenon; the plural “rainbows” is used for multiple rainbows or for individual examples.
A wide range or varied collection of colours, qualities, or possibilities.
"The festival featured a rainbow of music from around the world."
Common in the phrase “a rainbow of” and typically positive in tone, suggesting richness and variety.
Use the plural for multiple rainbows or when referring to the phenomenon in general.
"Two rainbows appeared over the harbour."
A rainbow is a full circle of colour formed from ordinary raindrops, turning a simple shower into a temporary arc across the sky.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does rainbow come from?
The word “rainbow” is an English compound formed in the Middle English period from “rain” and “bow,” meaning an arched or bow-shaped band of colour. Its components reflect the old observation that the coloured arc appears in connection with rain. The word “rain” itself comes from Proto-Germanic *regn-, while “bow” refers to a curved shape and has its own Germanic and Old English ancestry. The compound therefore combines the atmospheric condition with the arc’s visual form.
Related word forms
How rainbow is actually used
The literal sense is straightforward and generally neutral. Figurative senses, especially “a rainbow of” something, suggest variety, richness, or a lively range and are common in formal and informal writing.