Op"tics (?), n. [Cf. F. optique, L. optice, Gr. &?; (sc. &?;). See
Optic.] That branch of physical science which treats of the nature and
properties of light, the laws of its modification by opaque and
transparent bodies, and the phenomena of vision.
Op"ti*graph (?), n. [Optic + -graph: cf. F. opticographe. See Optic, a.
] A telescope with a diagonal eyepiece, suspended vertically in gimbals
by the object end beneath a fixed diagonal plane mirror. It is used for
delineating landscapes, by means of a pencil at the eye end which
leaves the delineation on paper.