n. A bow, or an arc of a circle, consisting of the prismatic colors, formed by the refraction and reflection of rays of light from drops of rain or vapor, appearing in the part of the heavens opposite to the sun.n. In heraldry, the representation of a half-ring divided into seven concentric narrow rings and arched upward, each end resting on a clump of clouds.n. In ornithology, a humming-bird of tho genus Diphlogena, containing two most brilliantly plumaged species, D. iris of Bolivia, and D. hesperus of Ecuador.n. The rainbow-fish.To color like a rainbow, or so brightly as to suggest the rainbow; curve over or surround, as with a rainbow.