Pronunciation: (rān'bō"),[key] —n. 1. a bow or arc of prismatic colors appearing in the heavens opposite the sun and caused by the refraction and reflection of the sun's rays in drops of rain. Cf. primary rainbow, secondary rainbow. 2. a similar bow of colors, esp. one appearing in the spray of a waterfall or fountain.
3. any brightly multicolored arrangement or display.
4. a wide variety or range; gamut.
5. a visionary goal: He pursued the rainbow of a singing career for years before becoming a success. 6. See rainbow trout.
—adj. made up of diverse races, ethnic groups, etc.: a rainbow coalition of supporters.