Binoculars, optical instrument consisting of a pair of compact telescopes mounted side by side. Since both eyes are used, the magnified image of distant objects appears to be in 3 dimensions. The magnifying power of a pair of binoculars and the diameter of the object lens (front lens) are engraved on the instrument. Binoculars marked 10 × 50, for example, will make objects appear 10 times closer and have object lenses that are 50 mm (about 6 in) in diameter. Binoculars can be adjusted to focus the image, to move the two telescopes nearer or farther apart to fit the eyes, and to remove double images.
21st Century Webster's Family Encyclopedia21st Century Webster's Family Encyclopedia - Bell's palsy to Black Friday