1738, "involving both eyes," earlier "having two eyes" (1713), from French binoculaire, from Latin bini "two by two, twofold, two apiece" (see binary) + ocularis "of the eye," from oculus "eye" (see eye (n.)). The double-tubed telescopic instrument (1871, short for binocular glass) earlier was called a binocle. Related: Binocularity.
