Ommatidium

Pronunciation

• IPA: /É’məˈtɪdɪəm/

Origin

From the stem form of Ancient Greek ὄμμα (omma, "eye") + -idium.

Full definition of ommatidium

Noun

1. (zoology) One of the conical substructures which make up the eyes of invertebrates.
• 1996: the ‘compound’ eyes of insects ... are made up of large numbers of facets or ommatidia, and in this sense, our own eyes are ‘simple’. — Michael J. Roberts, Spiders of Britain and Northern Europe (Collins 1996, p. 12)