https://doi.org/10.1351/goldbook.P04703
The classification of the symmetry elements of an object. It is denoted in the Schoenflies notation by an italic symbol, such as \(C_{3}\), \(D_{2}\), \(T_{\text{d}}\), etc.
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2213 [Terms] [Paper]