iris

noun6

1. •
   the ring in the eye that gives it its color and that opens and closes to let in more or less light
2. •
   A plant of the genus Iris, common in the northern hemisphere, and generally having attractive blooms (See Iris (plant) on Wikipedia.Wikipedia ).
3. •
   A diaphragm used to regulate the size of a hole, especially as a way of controlling the amount of light reaching a lens.
4. •
   A constricted opening in the path inside a waveguide, used to form a resonator.
5. •
   (literary) A rainbow, or other colourful refraction of light.
6. •
   The inner circle of an oscillated color spot.

verb2

1. •
   To open or close in the manner of an iris.
2. •
   (literary) To cause (something) to shine with the colours of the rainbow; to make iridescent.

   • Pure, transparent, glistening in the sun, and irised by a thousand hues, which float and wave and spread in graceful and ceaseless motion on its surface! — 1834

noun1

1. •
   Acronym of immune reconstitution inflammatory syndrome.