The DICT Development Group

  Perpendicular \Per`pen*dic"u*lar\, n.
     1. A line at right angles to the plane of the horizon; a
        vertical line or direction.
        [1913 Webster]
  
     2. (Geom.) A line or plane falling at right angles on another
        line or surface, or making equal angles with it on each
        side.
        [1913 Webster]

  Perpendicular \Per`pen*dic"u*lar\, a. [L. perpendicularis,
     perpendicularius: cf. F. perpendiculaire. See Perpendicle,
     Pension.]
     1. Exactly upright or vertical; pointing to the zenith; at
        right angles to the plane of the horizon; extending in a
        right line from any point toward the center of the earth.
        [1913 Webster]
  
     2. (Geom.) At right angles to a given line or surface; as,
        the line ad is perpendicular to the line bc.
        [1913 Webster]
  
     Perpendicular style (Arch.), a name given to the latest
        variety of English Gothic architecture, which prevailed
        from the close of the 14th century to the early part of
        the 16th; -- probably so called from the vertical style of
        its window mullions.
        [1913 Webster]

  perpendicular
       adj 1: intersecting at or forming right angles; "the axes are
              perpendicular to each other" [ant: oblique, parallel]
       2: at right angles to the plane of the horizon or a base line;
          "a vertical camera angle"; "the monument consists of two
          vertical pillars supporting a horizontal slab"; "measure
          the perpendicular height" [syn: vertical] [ant: inclined,
           horizontal]
       3: extremely steep; "the great perpendicular face of the cliff"
       n 1: a straight line at right angles to another line
       2: a Gothic style in 14th and 15th century England;
          characterized by vertical lines and a four-centered
          (Tudor) arch and fan vaulting [syn: perpendicular style,
           English-Gothic, English-Gothic architecture]
       3: a cord from which a metal weight is suspended pointing
          directly to the earth's center of gravity; used to
          determine the vertical from a given point [syn: plumb
          line]
       4: an extremely steep face

  49 Moby Thesaurus words for "perpendicular":
     air line, axis, azimuth circle, beeline, chord, diagonal, diameter,
     direct line, directrix, edge, erect, great-circle course, normal,
     orthodiagonal, orthogonal, orthometric, plumb, plunging,
     precipitous, radius, radius vector, rectangular, right angle,
     right line, right-angle, right-angled, right-angular, secant,
     segment, sheer, shortcut, side, stand-up, steep, straight,
     straight course, straight line, straight stretch, straight-up,
     straight-up-and-down, straightaway, streamline, tangent,
     transversal, up-and-down, upright, vector, vertical,
     vertical circle