stereoisomers that can be interconverted (actually or conceptually) by torsion about a bond axis. This includes
E,Z-isomers of alkenes, atropisomers and rotamers.
Source:
PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2221 (https://doi.org/10.1351/pac199668122193)