Schläfli Symbol
A symbol of the form {p, q, r, ...} used to describe regular polygons, polyhedra, and their higher-dimensional counterparts. The symbol {p} denotes a regular polygon for integer p, or a star polygon for rational p. The symbol {p, q} denotes a tessellation of regular p-gons, with q of them surrounding each polytope vertex. The Schläfli symbol can also be used to describe Platonic solids and Kepler-Poinsot solids, and a generalized version describes quasiregular polyhedra and Archimedean solids. Higher dimensional symbols can be used to describe the regular polychora and polytopes.