A Notation for Polyhedra which begins by specifying a ``seed'' polyhedron using a capital letter. The Platonic Solids are denoted T (Tetrahedron), O (Octahedron), C (Cube), I (Icosahedron), and D (Dodecahedron), according to their first letter. Other polyhedra include the Prisms, P, Antiprisms, A, and Pyramids, Y, where specifies the number of sides of the polyhedron's base.
Operations to be performed on the polyhedron are then specified with lower-case letters preceding the capital letter.
See also Polyhedron, Schläfli Symbol, Wythoff Symbol
References
Hart, G. ``Conway Notation for Polyhedra.''
http://www.li.net/~george/virtual-polyhedra/conway_notation.html.