A bow or arch exhibiting, in concentric bands, the several colors of the spectrum, and formed in the part of the hemisphere opposite to the sun by the refraction and reflection of the sun's rays in drops of falling rain.
- An arc of spectral colors, usually identified as red, orange, yellow, green, blue, indigo, and violet, that appears in the sky opposite the sun as a result of the refractive dispersion of sunlight in drops of rain or mist.
- A similar arc or band, as one produced by a prism or by iridescence.
- A graded display of colors.
- An illusory hope: chasing the rainbow of overnight success.
- A diverse assortment or collection.