A solid body whose base is a square, triangle, or polygon, and its sides plane triangles, meeting at top in one common point. Architecturally, it applies to the great mounds of stone or brickwork found in Egypt, and in some other countries. The largest of the pyramids is that built by Cheops, on the plain of the Nile. This has a square base, each side of which measures 763.4 feet, while its height is 480 feet. The pyramids contain sepulchral chambers, in which the bodies of the Pharaohs were buried.