Op"tic(p"tk), n. [From Optic, a.] 1. The organ of sight; an eye.
The difference is as great betweenPope.
The optics seeing, as the object seen.
2. An eyeglass.
Op"tic*al(p"t*kl), } a. [F. optique, Gr. 'optiko`s; akin to 'o`psis sight, 'o`pwpa I have seen, 'o`psomai I shall see, and to 'o`sse the two eyes, 'o`ps face, L. oculus eye. See Ocular, Eye, and cf. Canopy, Ophthalmia.] 1. Of, pertaining to, or using vision or sight; as, optical illusions. [wns=2]
Syn. -- ocular, optic, visual.
[1913 Webster + WordNet 1.5]
The moon, whose orbMilton.
Through optic glass the Tuscan artist views.
2. Of or pertaining to the eye; ocular; as, the
optic nerves (the first pair of cranial nerves) which are distributed to the retina; the optic (or
optical) axis of the eye. See Illust. of Brain, and Eye. [wns=3]
3. Relating to the science of optics or to devices designed to assist vision; as,
optical equipment. [wns=1]
[1913 Webster +PJC]
(Opt.), the angle included between the optic axes of the two eyes when directed to the same point; -- sometimes called
binocular parallax. --
(Opt.) (a) A line drawn through the center of the eye perpendicular to its anterior and posterior surfaces. In a normal eye it is in the direction of the optic axis that objects are most distinctly seen. (b) The line in a doubly refracting crystal, in the direction of which no double refraction occurs. A uniaxial crystal has one such line, a biaxial crystal has two. --
(Opt.), a graduated circle used for the measurement of angles in optical experiments. --
Optical square, a surveyor's instrument with reflectors for laying off right angles.
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Sun 18th August 2019