The term of eyesight can be summarized by the crossword solution of OPTIC. OPTIC is an adjective that refers to the sense of sight, or vision. It is derived from the Greek word optikos, which means 'of sight'. OPTIC is also used to describe any device or instrument that aids in the perception of light, such as a telescope or microscope. In addition, it is used to describe any optical device or system, such as lenses, mirrors, and prisms.