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1630s, from Late Latin monoculus "one-eyed," from Greek monos "alone, single" (see mono-) + Latin oculus "eye" (see eye (n.)).
monocular mo·noc·u·lar (mŏ-nŏk'yə-lər, mə-)adj.
Having or affecting one eye only.
Having a single eyepiece, as certain microscopes or other optical instruments.