irises

i·ris   (ī'rĭs)    n.   pl. i·ris·es or i·ri·des (ī'rĭ-dēz', ĭr'ĭ-) The pigmented, round, contractile membrane of the eye, suspended between the cornea and lens and perforated by the pupil. It regulates the amount of light entering the eye. Any of numerous plants of the genus Iris, having narrow sword-shaped leaves and showy, variously colored flowers. A rainbow or rainbowlike display of colors. An iris diaphragm. [Middle English, iris (the plant), from Latin īris, īrid-, rainbow, iris (the plant), from Greek, rainbow, brightly-colored gemstone, iris of the eye; see wei- in Indo-European roots.]

iris [(eye-ris)]

The colored membrane of the eye, surrounding the pupil, which by contracting and expanding regulates the amount of light that enters the eye.

iris 

Main Entry: iris
Pronunciation: 'I-r&s
Function: noun
Inflected Form: plural iris·es or iri·des /'I-r&-"dEz,'ir-&-/
1 : the opaque muscular contractile diaphragm that is suspended in the aqueous humor in front of the lens of the eye, is perforated by the pupil and is continuousperipherally with the ciliary body, has a deeply pigmented posterior surface which excludes the entrance of light except through the pupil and a colored anterior surface which determines the color ofthe eyes
2 : IRIS DIAPHRAGM

iris i·ris (ī'rĭs)
n. pl. i·ris·es or i·ri·des (ī'rĭ-dēz', ĭr'ĭ-)
The round pigmented contractile membrane of the eye that is perforated in the center by the pupil, forms the front part of the vascular tunic, and is attached on the margin to the ciliary body.

---

i'ri·dal (ī'rĭ-dl, ĭr'ĭ-) or i·rid'i·al (ī-rĭd'ē-əl, ĭ-rĭd'-) or i·rid'i·an adj.

iris   (ī'rĭs)  Pronunciation Key  Plural irises or irides (ī'rĭ-dēz', ĭr'ĭ-) The colored, muscular ring around the pupil of the eye in vertebrate animals, located between the cornea and lens. Contraction and expansion of the iris controls the size of the pupil, thereby regulating the amount of light reaching the retina.