n. The rainbow.n. [capitalized] In classical mythology, the goddess of the rainbow and messenger of the gods, attached especially to Hera.n. [capitalized] The seventh planetoid, discovered by Hind at London in 1847.n. An appearance resembling a rainbow; an appearance of the hues of a rainbow, as seen in sunlit spray, the spectrum of sunlight, etc.; any iridescence.n. A precious stone.n. In anatomy, a contraetile colored curtain suspended vertically in the aqueous humor of the eye, between the cornea and the lens, separating the anterior and posterior chambers, which intercommunicate through the pupil.n. In entomology, the first or inner ring of an ocellated spot, adjoining the pupil, being a light-colored circle with a dark center and outer border.n. [capitalized] [NL. (Linnæus).] A genus of monocotyledonous plants of the natural order Irideæ, tribe Moræeæ, having the perianth 6-parted, the 3 outer divisions spreading or reflexed, and the 3 inner smaller and erect.n. A plant of the genus Iris.n. The root of a species of iris cultivated in India and sold in the bazaars of Calcutta to be used, like the Florentine orris-root, in perfumery and medicine.n. The iridescence in fractured pieces of rock-crystal.