Webster's Revised Unabridged Dictionary · 1913

Ocular

Ocular , adjective

[Latin ocularis, ocularius, from oculus the eye: compare French oculaire. See Eye, and compare Antler, Inveigle.]

1.
Depending on, or perceived by, the eye; received by actual sight; personally seeing or having seen; as, ocular proof. — Shakespeare
Thomas was an ocular witness of Christ's death. — South
2.
(Anatomy) Of or pertaining to the eye; optic.

Ocular , noun

(Optics) The eyepiece of an optical instrument, as of a telescope or microscope.