1. 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
   "Her striking blue iris contrasted beautifully with her dark lashes"
    
2. Plants with sword-shaped leaves and erect stalks bearing bright-coloured flowers composed of three petals and three drooping sepals
   "The purple iris bloomed along the garden path";
   - flag, fleur-de-lis, sword lily
    
3. Diaphragm consisting of thin overlapping plates that can be adjusted to change the diameter of a central opening
   "The camera's iris diaphragm controlled the amount of light entering the lens";
   - iris diaphragm

Derived forms: irises, irides

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

Part of: eye, genus Iris, oculus [rare], optic

Encyclopedia: Iris, The Happy Professor