iris
noun
1. plants with sword-shaped leaves and erect stalks bearing bright-colored flowers composed of three petals and three drooping sepals
Similar word(s): flag
Definition categories: plant
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 colored portion of the eye
Definition categories: body, membrane
3. diaphragm consisting of thin overlapping plates that can be adjusted to change the diameter of a central opening
verb
1. (of an aperture, lens, or door) To open or close in the manner of an iris.