eyeglass \ˈ ̷ ̷ˌ ̷ ̷\noun 1. a.obsolete: the lens of the eye b.: the eyepiece of an optical instrument (as a microscope or a telescope) c.: a lens for personal wear that is used to aid vision or correct defects of vision; specifically: monocle d.eyeglassesplural: glasses, spectacles 2.: eyecup 1a