\Ge`o*met"ric\, Geometrical \Ge`o*met"ric*al\, a. [L.
geometricus; Gr. ?: cf. F. g['e]om['e]trique.]
Pertaining to, or according to the rules or principles of,
geometry; determined by geometry; as, a geometrical solution
of a problem.
Note: Geometric is often used, as opposed to algebraic, to
      include processes or solutions in which the
      propositions or principles of geometry are made use of
      rather than those of algebra.
Note: Geometrical is often used in a limited or strictly
      technical sense, as opposed to mechanical; thus, a
      construction or solution is geometrical which can be
      made by ruler and compasses, i. e., by means of right
      lines and circles. Every construction or solution which
      requires any other curve, or such motion of a line or
      circle as would generate any other curve, is not
      geometrical, but mechanical. By another distinction, a
      geometrical solution is one obtained by the rules of
      geometry, or processes of analysis, and hence is exact;
      while a mechanical solution is one obtained by trial,
      by actual measurements, with instruments, etc., and is
      only approximate and empirical.
{Geometrical curve}. Same as {Algebraic curve}; -- so called
   because their different points may be constructed by the
   operations of elementary geometry.
{Geometric lathe}, an instrument for engraving bank notes,
   etc., with complicated patterns of interlacing lines; --
   called also {cycloidal engine}.
{Geometrical pace}, a measure of five feet.
{Geometric pen}, an instrument for drawing geometric curves,
   in which the movements of a pen or pencil attached to a
   revolving arm of adjustable length may be indefinitely
   varied by changing the toothed wheels which give motion to
   the arm.
{Geometrical plane} (Persp.), the same as {Ground plane} .
{Geometrical progression}, {proportion}, {ratio}. See under
   {Progression}, {Proportion} and {Ratio}.
{Geometrical radius}, in gearing, the radius of the pitch
   circle of a cogwheel. --Knight.
{Geometric spider} (Zo["o]l.), one of many species of
   spiders, which spin a geometrical web. They mostly belong
   to {Epeira} and allied genera, as the garden spider. See
   {Garden spider}.
{Geometric square}, a portable instrument in the form of a
   square frame for ascertaining distances and heights by
   measuring angles.
{Geometrical staircase}, one in which the stairs are
   supported by the wall at one end only.
{Geometrical tracery}, in architecture and decoration,
   tracery arranged in geometrical figures.