\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.
2. (Geom.) At right angles to a given line or surface; as,
   the line ad is perpendicular to the line bc.
{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.

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