A flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center. A plant with sword-shaped leaves and showy flowers, typically purple, yellow, or white. Native to both Eurasia and North America, it is widely cultivated as an ornamental. A rainbow or a rainbowlike appearance. (of an aperture, typically that of a lens) open or close in the manner of an iris or iris diaphragm. The goddess of the rainbow, who acted as a messenger of the gods.