The Collaborative International Dictionary
Dioptrical
Dioptric \Di*op"tric\, Dioptrical \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.
Wiktionary
dioptrical
a. (alternative form of dioptric English)