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3 definitions found
 for Double refraction
From The Collaborative International Dictionary of English v.0.48 :

  Refraction \Re*frac"tion\ (r?*fr?k"sh?n), n. [F. r['e]fraction.]
     1. The act of refracting, or the state of being refracted.
        [1913 Webster]
  
     2. The change in the direction of ray of light, heat, or the
        like, when it enters obliquely a medium of a different
        density from that through which it has previously moved.
        [1913 Webster]
  
              Refraction out of the rarer medium into the denser,
              is made towards the perpendicular.    --Sir I.
                                                    Newton.
        [1913 Webster]
  
     3. (Astron.)
        (a) The change in the direction of a ray of light, and,
            consequently, in the apparent position of a heavenly
            body from which it emanates, arising from its passage
            through the earth's atmosphere; -- hence distinguished
            as atmospheric refraction, or astronomical refraction.
        (b) The correction which is to be deducted from the
            apparent altitude of a heavenly body on account of
            atmospheric refraction, in order to obtain the true
            altitude.
            [1913 Webster]
  
     Angle of refraction (Opt.), the angle which a refracted ray
        makes with the perpendicular to the surface separating the
        two media traversed by the ray.
  
     Conical refraction (Opt.), the refraction of a ray of light
        into an infinite number of rays, forming a hollow cone.
        This occurs when a ray of light is passed through crystals
        of some substances, under certain circumstances. Conical
        refraction is of two kinds; external conical refraction,
        in which the ray issues from the crystal in the form of a
        cone, the vertex of which is at the point of emergence;
        and internal conical refraction, in which the ray is
        changed into the form of a cone on entering the crystal,
        from which it issues in the form of a hollow cylinder.
        This singular phenomenon was first discovered by Sir W. R.
        Hamilton by mathematical reasoning alone, unaided by
        experiment.
  
     Differential refraction (Astron.), the change of the
        apparent place of one object relative to a second object
        near it, due to refraction; also, the correction required
        to be made to the observed relative places of the two
        bodies.
  
     Double refraction (Opt.), the refraction of light in two
        directions, which produces two distinct images. The power
        of double refraction is possessed by all crystals except
        those of the isometric system. A uniaxial crystal is said
        to be optically positive (like quartz), or optically
        negative (like calcite), or to have positive, or negative,
        double refraction, according as the optic axis is the axis
        of least or greatest elasticity for light; a biaxial
        crystal is similarly designated when the same relation
        holds for the acute bisectrix.
  
     Index of refraction. See under Index.
  
     Refraction circle (Opt.), an instrument provided with a
        graduated circle for the measurement of refraction.
  
     Refraction of latitude, longitude, declination, right
     ascension, etc., the change in the apparent latitude,
        longitude, etc., of a heavenly body, due to the effect of
        atmospheric refraction.
  
     Terrestrial refraction, the change in the apparent altitude
        of a distant point on or near the earth's surface, as the
        top of a mountain, arising from the passage of light from
        it to the eye through atmospheric strata of varying
        density.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 :

  Double \Dou"ble\ (d[u^]b"'l), a. [OE. doble, duble, double, OF.
     doble, duble, double, F. double, fr. L. duplus, fr. the root
     of duo two, and perh. that of plenus full; akin to Gr.
     diplo`os double. See Two, and Full, and cf. Diploma,
     Duple.]
     1. Twofold; multiplied by two; increased by its equivalent;
        made twice as large or as much, etc.
        [1913 Webster]
  
              Let a double portion of thy spirit be upon me. -- 2
                                                    Kings ii. 9.
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              Darkness and tempest make a double night. --Dryden.
        [1913 Webster]
  
     2. Being in pairs; presenting two of a kind, or two in a set
        together; coupled.
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              [Let] The swan, on still St. Mary's lake,
              Float double, swan and shadow.        --Wordsworth.
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     3. Divided into two; acting two parts, one openly and the
        other secretly; equivocal; deceitful; insincere.
        [1913 Webster]
  
              With a double heart do they speak.    -- Ps. xii. 2.
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     4. (Bot.) Having the petals in a flower considerably
        increased beyond the natural number, usually as the result
        of cultivation and the expense of the stamens, or stamens
        and pistils. The white water lily and some other plants
        have their blossoms naturally double.
        [1913 Webster]
  
     Note: Double is often used as the first part of a compound
           word, generally denoting two ways, or twice the number,
           quantity, force, etc., twofold, or having two.
           [1913 Webster]
  
     Double base, or Double bass (Mus.), the largest and
        lowest-toned instrument in the violin form; the
        contrabasso or violone.
  
     Double convex. See under Convex.
  
     Double counterpoint (Mus.), that species of counterpoint or
        composition, in which two of the parts may be inverted, by
        setting one of them an octave higher or lower.
  
     Double court (Lawn Tennis), a court laid out for four
        players, two on each side.
  
     Double dagger (Print.), a reference mark ([dag]) next to
        the dagger ([dagger]) in order; a diesis.
  
     Double drum (Mus.), a large drum that is beaten at both
        ends.
  
     Double eagle, a gold coin of the United States having the
        value of 20 dollars.
  
     Double entry. See under Bookkeeping.
  
     Double floor (Arch.), a floor in which binding joists
        support flooring joists above and ceiling joists below.
        See Illust. of Double-framed floor.
  
     Double flower. See Double, a., 4.
  
     Double-framed floor (Arch.), a double floor having girders
        into which the binding joists are framed.
  
     Double fugue (Mus.), a fugue on two subjects.
  
     Double letter.
        (a) (Print.) Two letters on one shank; a ligature.
        (b) A mail requiring double postage.
  
     Double note (Mus.), a note of double the length of the
        semibreve; a breve. See Breve.
  
     Double octave (Mus.), an interval composed of two octaves,
        or fifteen notes, in diatonic progression; a fifteenth.
  
     Double pica. See under Pica.
  
     Double play (Baseball), a play by which two players are put
        out at the same time.
  
     Double plea (Law), a plea alleging several matters in
        answer to the declaration, where either of such matters
        alone would be a sufficient bar to the action. --Stephen.
  
     Double point (Geom.), a point of a curve at which two
        branches cross each other. Conjugate or isolated points of
        a curve are called double points, since they possess most
        of the properties of double points (see Conjugate). They
        are also called acnodes, and those points where the
        branches of the curve really cross are called crunodes.
        The extremity of a cusp is also a double point.
  
     Double quarrel. (Eccl. Law) See Duplex querela, under
        Duplex.
  
     Double refraction. (Opt.) See Refraction.
  
     Double salt. (Chem.)
        (a) A mixed salt of any polybasic acid which has been
            saturated by different bases or basic radicals, as the
            double carbonate of sodium and potassium,
            NaKCO3.6H2O.
        (b) A molecular combination of two distinct salts, as
            common alum, which consists of the sulphate of
            aluminium, and the sulphate of potassium or ammonium.
            
  
     Double shuffle, a low, noisy dance.
  
     Double standard (Polit. Econ.), a double standard of
        monetary values; i. e., a gold standard and a silver
        standard, both of which are made legal tender.
  
     Double star (Astron.), two stars so near to each other as
        to be seen separate only by means of a telescope. Such
        stars may be only optically near to each other, or may be
        physically connected so that they revolve round their
        common center of gravity, and in the latter case are
        called also binary stars.
  
     Double time (Mil.). Same as Double-quick.
  
     Double window, a window having two sets of glazed sashes
        with an air space between them.
        [1913 Webster]

From WordNet (r) 3.0 (2006) :

  double refraction
      n 1: splitting a ray into two parallel rays polarized
           perpendicularly [syn: double refraction, birefringence]

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