In this work, we introduce torsion angular bin strings (TABS) to capture the conformational space of a molecule in terms of its torsion angles. We also introduce a new 2D flexibility descriptor, nTABS, that gives the number of distinct TABS for a molecule and thus provides an estimate for the number of representative conformers. Though nTABS is a 2D descriptor (i.e., calculated solely from the molecular topology), it relies upon reference data or parameters generated from 3D information of a large number of molecules (see below). This is similar to other common 2D descriptors like the topological polar surface area (TPSA) and van der Waals surface area (VSA) . In contrast to Kier φ, nTABS is able to account for specified/unspecified stereochemistry and the differences in conformational flexibility in regioisomers. A TABS itself is a vector representation for a conformer reduced to a description of its dihedral angles: Each vector element corresponds to the binned value of the torsion about one rotatable bond in the molecule. The TABS representation discretizes the torsion space and is a form of dimensionality reduction that simplifies the analysis and understanding of conformational ensembles. After this definition, it is also clear that TABS and a torsion fingerprint (TF) are inherently different as the TFs operate on a continuous space, as well as treating ring contributions as average sums. TFD itself and TABS are only comparable at all if a distance metric between to TABS was defined, which has not been done as part of this initial method development.