optic angle

Optic \Op"tic\ ([o^]p"t[i^]k), Optical \Op"tic*al\
   ([o^]p"t[i^]*kal), 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. [WordNet sense 2]

   Syn: ocular, optic, visual.
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              The moon, whose orb
              Through optic glass the Tuscan artist views.
                                                  --Milton.
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   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}. [WordNet sense 3]
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   3. Relating to the science of optics or to devices designed
      to assist vision; as, optical works; optical equipment.
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   {Optic angle} (Opt.), the angle included between the optic
      axes of the two eyes when directed to the same point; --
      sometimes called {binocular parallax}.

   {Optic axis}. (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.

   {Optical circle} (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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Angle \An"gle\ ([a^][ng]"g'l), n. [F. angle, L. angulus angle,
   corner; akin to uncus hook, Gr. 'agky`los bent, crooked,
   angular, 'a`gkos a bend or hollow, AS. angel hook, fish-hook,
   G. angel, and F. anchor.]
   1. The inclosed space near the point where two lines meet; a
      corner; a nook.
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            Into the utmost angle of the world.   --Spenser.
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            To search the tenderest angles of the heart.
                                                  --Milton.
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   2. (Geom.)
      (a) The figure made by. two lines which meet.
      (b) The difference of direction of two lines. In the lines
          meet, the point of meeting is the vertex of the angle.
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   3. A projecting or sharp corner; an angular fragment.
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            Though but an angle reached him of the stone.
                                                  --Dryden.
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   4. (Astrol.) A name given to four of the twelve astrological
      "houses." [Obs.] --Chaucer.
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   5. [AS. angel.] A fishhook; tackle for catching fish,
      consisting of a line, hook, and bait, with or without a
      rod.
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            Give me mine angle: we 'll to the river there.
                                                  --Shak.
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            A fisher next his trembling angle bears. --Pope.
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   {Acute angle}, one less than a right angle, or less than
      90[deg].

   {Adjacent} or {Contiguous angles}, such as have one leg
      common to both angles.

   {Alternate angles}. See {Alternate}.

   {Angle bar}.
      (a) (Carp.) An upright bar at the angle where two faces of
          a polygonal or bay window meet. --Knight.
      (b) (Mach.) Same as {Angle iron}.

   {Angle bead} (Arch.), a bead worked on or fixed to the angle
      of any architectural work, esp. for protecting an angle of
      a wall.

   {Angle brace}, {Angle tie} (Carp.), a brace across an
      interior angle of a wooden frame, forming the hypothenuse
      and securing the two side pieces together. --Knight.

   {Angle iron} (Mach.), a rolled bar or plate of iron having
      one or more angles, used for forming the corners, or
      connecting or sustaining the sides of an iron structure to
      which it is riveted.

   {Angle leaf} (Arch.), a detail in the form of a leaf, more or
      less conventionalized, used to decorate and sometimes to
      strengthen an angle.

   {Angle meter}, an instrument for measuring angles, esp. for
      ascertaining the dip of strata.

   {Angle shaft} (Arch.), an enriched angle bead, often having a
      capital or base, or both.

   {Curvilineal angle}, one formed by two curved lines.

   {External angles}, angles formed by the sides of any
      right-lined figure, when the sides are produced or
      lengthened.

   {Facial angle}. See under {Facial}.

   {Internal angles}, those which are within any right-lined
      figure.

   {Mixtilineal angle}, one formed by a right line with a curved
      line.

   {Oblique angle}, one acute or obtuse, in opposition to a
      right angle.

   {Obtuse angle}, one greater than a right angle, or more than
      90[deg].

   {Optic angle}. See under {Optic}.

   {Rectilineal} or {Right-lined angle}, one formed by two right
      lines.

   {Right angle}, one formed by a right line falling on another
      perpendicularly, or an angle of 90[deg] (measured by a
      quarter circle).

   {Solid angle}, the figure formed by the meeting of three or
      more plane angles at one point.

   {Spherical angle}, one made by the meeting of two arcs of
      great circles, which mutually cut one another on the
      surface of a globe or sphere.

   {Visual angle}, the angle formed by two rays of light, or two
      straight lines drawn from the extreme points of an object
      to the center of the eye.

   {For Angles of commutation}, {draught}, {incidence},
   {reflection}, {refraction}, {position}, {repose}, {fraction},
      see {Commutation}, {Draught}, {Incidence}, {Reflection},
      {Refraction}, etc.
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