What is Schoenflies symbol?

A point group is named by its Schoenflies symbol: $C_n$ (one $C_n$ axis), $C_{nv}$ (adding $n$ vertical planes), $C_{nh}$ (adding $\sigma_h$), $D_n$ (adding $n$ $C_2$ axes perpendicular to $C_n$), $D_{nh}$ and $D_{nd}$ (adding $\sigma_h$, or $n$ dihedral planes, to $D_n$), $S_{2n}$, the cubic groups $T_d$, $O_h$, $I_h$ of the tetrahedron, octahedron and icosahedron, and $C_s$, $C_i$, $C_1$ for molecules with only a mirror plane, only an inversion centre, or nothing at all. Linear molecules belong to $C_{\infty v}$ or $D_{\infty h}$.