n. 1. A lens of glass worn in front of the eye to assist vision; -- usually used in the plural, referring to a pair of lenses fixed together in a frame, and worn resting on the bridge of the nose, to improve the vision. A single eyeglass in a frame is called a monocle. [ 1913 Webster +PJC ]
2. Eyepiece of a telescope, microscope, etc. [ 1913 Webster ]
n. pl. a pair of lenses fixed together in a frame, used for correcting defective vision. Also called a pair of eyeglasses. See also eyeglass{ 1 }. Syn. -- spectacles, specs, glasses. [ WordNet 1.5 +PJC ]