{ Di*op"tric (?), Di*op"tric*al (?), } a. [Gr. &?; belonging to the use of the &?;; &?; = dia` through + the root of &?; I shall see: cf. F. dioptrique.] Of or pertaining to dioptrics; assisting vision by means of the refraction of light; refractive; as, the dioptric system; a dioptric glass or telescope. "Dioptrical principles." Nichol.

Dioptric curve(Geom.), a Cartesian oval. See under Cartesian.