parallel ruler

Parallel \Par"al*lel\, a. [F. parall[`e]le, L. parallelus, fr.
   Gr. ?; para` beside + ? of one another, fr. ? other, akin to
   L. alius. See {Alien}.]
   1. (Geom.) Extended in the same direction, and in all parts
      equally distant; as, parallel lines; parallel planes.
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            Revolutions . . . parallel to the equinoctial.
                                                  --Hakluyt.
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   Note: Curved lines or curved planes are said to be parallel
         when they are in all parts equally distant.
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   2. Having the same direction or tendency; running side by
      side; being in accordance (with); tending to the same
      result; -- used with to and with.
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            When honor runs parallel with the laws of God and
            our country, it can not be too much cherished.
                                                  --Addison.
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   3. Continuing a resemblance through many particulars;
      applicable in all essential parts; like; similar; as, a
      parallel case; a parallel passage. --Addison.
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   {Parallel bar}.
      (a) (Steam Eng.) A rod in a parallel motion which is
          parallel with the working beam.
      (b) One of a pair of bars raised about five feet above the
          floor or ground, and parallel to each other, -- used
          for gymnastic exercises.

   {Parallel circles of a sphere}, those circles of the sphere
      whose planes are parallel to each other.

   {Parallel columns}, or {Parallels} (Printing), two or more
      passages of reading matter printed side by side, for the
      purpose of emphasizing the similarity or discrepancy
      between them.

   {Parallel forces} (Mech.), forces which act in directions
      parallel to each other.

   {Parallel motion}.
      (a) (Mach.) A jointed system of links, rods, or bars, by
          which the motion of a reciprocating piece, as a piston
          rod, may be guided, either approximately or exactly in
          a straight line. --Rankine.
      (b) (Mus.) The ascending or descending of two or more
          parts at fixed intervals, as thirds or sixths.

   {Parallel rod} (Locomotive Eng.), a metal rod that connects
      the crank pins of two or more driving wheels; -- called
      also {couping rod}, in distinction from the connecting
      rod. See Illust. of {Locomotive}, in App. -- {Parallel
   ruler}, an instrument for drawing parallel lines, so
      constructed as to have the successive positions of the
      ruling edge parallel to each other; also, one consisting
      of two movable parts, the opposite edges of which are
      always parallel.

   {Parallel sailing} (Naut.), sailing on a parallel of
      latitude.

   {Parallel sphere} (Astron. & Geog.), that position of the
      sphere in which the circles of daily motion are parallel
      to the horizon, as to an observer at either pole.

   {Parallel vise}, a vise having jaws so guided as to remain
      parallel in all positions.
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Ruler \Rul"er\ (r[udd]l"[~e]r), n.
   1. One who rules; one who exercises sway or authority; a
      governor.
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            And he made him ruler over all the land. --Gen. xli.
                                                  43.
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            A prince and ruler of the land.       --Shak.
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   2. A straight or curved strip of wood, metal, etc., with a
      smooth edge, used for guiding a pen or pencil in drawing
      lines. Cf. {Rule}, n., 7
      (a) .
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   {Parallel ruler}. See under {Parallel}.
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