Pyramid

n. [Fr. pyramide, Sp. & It. piramide, Lat. pyramis, pyramides, from Gr. πυραμίς, πυραμίδος, Egypt. piromi.]

1. A solid body standing on a triangular, square, or polygonal base, and terminating in a point at the top.
2. (Geom.) A solid figure contained by several triangles, whose bases are all in the same plane, and which have one common vertex.
3. Especially, an edifice in the shape above described; as, the pyramids of Egypt.

They take the flow o' the Nile By certain scales i' the pyramids. Shak. While those deputed to inter the slain, Heap with a rising pyramid the plain. Pope. Altitude of a pyramid, 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.—Right pyramid, a pyramid the axis of which is perpendicular to the base.