A multicoloured arch in the sky, produced by prismatic refraction of light within droplets of rain in the air.
Any prismatic refraction of light showing a spectrum of colours.
(often used with “of”) A wide assortment; a varied multitude.
a rainbow of possibilities
An illusion, mirage.
Many electoral promises are rainbows, vanishing soon after poll day.
A curveball, particularly a slow one.
In Texas hold 'em or Omaha hold 'em, a flop that contains three different suits.
Rainbow trout.
To brighten with, or as with, a rainbow; to pattern with the colours of the rainbow.
To take the appearance of a rainbow.