Generally, a face is a component polygon, polyhedron, or polytope. A two‐dimensional face thus has vertices and edges, and can be used to make cells. More formally, a face is the intersection of an n‐dimensional polytope with a tangent hyperplane. Zero‐dimensional faces are known as polyhedron vertices nodes, one‐dimensional faces as polyhedron edges, n-2‐D faces as ridges, and n-1‐dimensional faces as facets. The illustration above illustrates the most commonly encountered face, namely that of a three‐dimensional polyhedron.
