Opposite: placed over against, or opposed to.

Optic: relating to the organs of vision.

Optic ganglia: are at the sides of the procerebrum and innervate the compound eyes.

Optic lobes: the laterals lobes of the procerebrum in which are centered the nerves supplying the organs of vision.

Opticon: the first of a series of three ganglionic swellings in the optic nerve: see epiopticon and periopticon.

Optic segment: =procerebral segment; q.

Optic tract: is the perceptive portion of the compound eye.

Ora: a border: specifically in some Coleoptera, the lateral margin of prothorax.

Ora coleopterorum: the margin of the elytra.

Orad: toward the mouth.