Iris

Pronunciation

• enPR: Ä«'rÄ­s, IPA: /ˈaɪɹɪs/
• Rhymes: -aɪɹɪs

Origin

From Middle English, from Latin, from Ancient Greek ἶρις (iris, "rainbow"), from Proto-Indo-European *wei-ro- ("a twist, thread, cord, wire"), from Proto-Indo-European *wei- ("to turn, twist, weave, plait").

Noun

1. (botany) A plant of the genus Iris, common in the northern hemisphere, and generally having attractive blooms (Iris (plant)).
• 1907, w, The Younger Set Chapter 5, Breezes blowing from beds of iris quickened her breath with their perfume ; she saw the tufted lilacs sway in the wind, and the streamers of rose-tinted wistaria swinging, all a-glisten with golden bees ; … .
2. (anatomy) The contractile membrane perforated by the pupil, which adjusts to control the amount of light reaching the retina, and which forms the colored portion of the eye (Iris (anatomy)).
3. (photography, cinematography) A diaphragm used to regulate the size of a hole, especially as a way of controlling the amount of light reaching a lens.
4. (poetic) A rainbow, or other colourful refraction of light.
5. (electronics) A constricted opening in the path inside a waveguide, used to form a resonator.

Derived terms

• iridal
• iridial
• iridian
• iridium
• iridocyclitis
• iridology
• Iris (proper name)
• iritis

Usage notes

For the part of the eye, the usual medical plural is irides.

iris and irises are in common use.

Full definition of iris

Verb

1. (of an aperture, lens, or door) To open or close in the manner of an iris.----