Webster's Revised Unabridged Dictionary · 1913

Monocular

Monocular , adjective

[Latin monoculus; Greek mo`nos single + Latin oculus eye: compare French monoculaire.]

1.
Having only one eye; with one eye only; as, monocular vision.
2.
Adapted to be used with only one eye at a time; as, a monocular microscope.