Gē'o-mĕt'ric or Gē'o-mĕt'ric-al, a.

a. [Fr. géométrique, Gr. γεωμετρικός.] Pertaining to, or according to, the rules or principles of geometry; determined by geometry; as, a geometrical solution of a problem.

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, and ratio. See PROGRESSION, PROPORTION, and RATIO. — Geometrical staircase, one in which the stairs are supported by the wall at one end only.

☞ 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 the ruler and compasses, that is, by means of right lines and circles. Every construction or solution which requires any other curve, or such a motion of a line or circle as would generate any other curve, is not geometrical, but mechanical. There is also another distinction sometimes observed, in accordance with which, 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, and the like, and is therefore only approximative and empirical.