In geometry, a face of a polyhedron is any of the polygons that make up its boundaries. For example, any of the squares that bound a cube is a face of the cube. The suffix -hedron is derived from the Greek word ἕδρα (hedra) which means "face". Sometimes, in the case of a pyramid, the term face is understood to exclude the base. The (two-dimensional) polygons that bound higher-dimensional polytopes are also commonly called faces.