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Noun: iris (irises,irides)  I-ris
  1. Plants with sword-shaped leaves and erect stalks bearing bright-coloured flowers composed of three petals and three drooping sepals
    - flag, fleur-de-lis, sword lily
  2. Muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye; it forms the coloured portion of the eye
  3. Diaphragm consisting of thin overlapping plates that can be adjusted to change the diameter of a central opening
    - iris diaphragm

Derived forms: irises, irides

Type of: diaphragm, iridaceous plant, membrane, stop, tissue layer

Part of: eye, genus Iris, oculus, optic

Encyclopedia: Iris, The Happy Professor