What is an irides?

Plural irises 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.

How do you pluralize iris?

Usage notes

For the part of the eye, the usual medical plural is irides. For the flower both iris and irises are in common use.