Ommatidium
Pronunciation : Om`ma*tid"i*um
Part of Speech : n.;
Etymology : [NL., dim. of Gr. (Zo?l.)
Definition : Defn: One of the single eyes forming the compound eyes of crustaceans, insects, and other invertebrates.
pl. Ommatidia.
Source : Webster's Unabridged Dictionary, 1913