A
pyramid (from ) is a
structure whose outer surfaces are triangular and converge to a single point at the top, making the shape roughly a
pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilateral, or any
polygon shape, meaning that a pyramid has at least three outer triangular surfaces (at least four
faces including the base). The
square pyramid, with square base and four triangular outer surfaces, is a common version.