OPTICS  , the

science of light, regarded as the medium of sight (Gr . 64as) . Generally the noun is qualified by an adjective so as to delimitate the principal groups of optical phenomena, e.g. geometrical optics, physical optics, meteorological optics, &c . Greek terminology included two adjectival forms—ra birruca, for all optical phenomena, including vision and the nature of light, and i b7rrtKI (sc . Bewpia), for the objective study of light, i.e. the nature of light itself and the theory of vision . See LIGHT and VISION .