ommatidium

One of the optical units, consisting of photoreceptors and usually one or more lenses, that make up a compound eye of an insect or a crustacean.

A radial element or segment of the compound eye of an arthropod.

One of the single eyes forming the compound eyes of crustaceans, insects, and other invertebrates; one of the eyes of an ommateum.

One of the conical substructures which make up the eyes of invertebrates.

any of the numerous small cone-shaped eyes that make up the compound eyes of some arthropods