The calculated molar refractivity of a molecule or substituent used as a measure of size and polarizability in 2D-QSAR.
Source:
PAC, 2016, 88, 239. 'Glossary of terms used in computational drug design, part II (IUPAC Recommendations 2015)' on page 242 (https://doi.org/10.1515/pac-2012-1204)