A pyramid is a solid, monumental construction of stacked masonry rising from a square or triangular base to a point, with smoothly sloping or bent walls uninterrupted by major setbacks. Pyramids were built by a few pre-modern societies, especially ancient Egypt, the Mayan civilization, and central Mexican cultures as tombs or for funereal or ceremonial purposes. There may be tunnels or hollow spaces within the pyramid, but hollow buildings shaped like a pyramid do not count as examples of this structural form.

The generally solid masonry mass has continuous sloping faces, which can include a bend without major terraces. Internal passages do not make it equivalent to a hollow pyramid-shaped building.

A step pyramid has large horizontal terraces interrupting its sloping form. Those major setbacks distinguish it from the smooth-sided or bent form described here.