Sailing Glossary - Term Rainbow

Any one of a family of circular arcs consisting of concentric colored bands, arranged from red on the inside to blue on the outside, which may be seen on a \sheet\"" of water drops (rain, fog, spray). The most common of the many possible is the primary rainbow. The second most common is the secondary rainbow, seen outside the primary bow and having the reverse spectral sequence. Tertiary and higher order bows are exceedingly rare due to their low luminosity. Supernumerary rainbows are seen fairly often just within the primary bow. ""