PYRAMID

pyramid. Pyramid, n. a square pillar ending in a point

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Pyr″a‐mid (?), n. [[L. pyramis, -idis, fr. Gr. �, �, of Egyptian origin: cf. F. pyramide.]] 1. 1. A solid body standing on a triangular, square, or polygonal base, and terminating in a point at the top; especially, a structure or edifice of this shape.
2. 2. (Geom.) A solid figure contained by a plane rectilineal figure as base and several triangles which have a common vertex and whose bases are sides of the base.
3. 3. pl. (Billiards) The game of pool in which the balls are placed in the form of a triangle at spot.
Altitude of a pyramid (Geom.), the perpendicular distance from the vertex to the plane of the base. — Axis of a pyramid (Geom.), a straight line drawn from the vertex to the center of the base. — Earth pyramid. (Geol.) See Earth pillars, under Earth. — Right pyramid (Geom.) a pyramid whose axis is perpendicular to the base.