n. pl. om·ma·tid·i·a (-ē-ə)
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.
[New Latin, diminutive of Greek omma, ommat-, eye; see okw- in the Appendix of Indo-European roots.]
om′ma·tidi·al (-ē-əl) adj.
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