conventional mass

symbol: $m_{\rm{c}}$
https://doi.org/10.1351/goldbook.09039
Mass of a body that is balanced by a standard mass under conventionally chosen conditions.
Notes:
  1. The International Organization of Legal Metrology recommends that the conventionally chosen conditions are: reference temperature, \(t_{\rm{ref}} = \pu{20 ^{\circ}C}\), density of air as a reference value, \(\rho_{0} = \pu{1.2 kg m−3}\); reference density of standard weight, \(\rho_{\rm{c}} = \pu{8000 kg m-3}\). In this case, the conventional mass is related to the mass (\(m\)) and density (\(\rho\)) of the object by \(m_{\rm{c}} = m \frac{1 - \rho_{0}/\rho}{1 - \rho_{0}/\rho_{\rm{c}}}\)
  2. The base unit of the quantity "conventional mass" is the kilogram.
Source:
PAC, 2025, 97, 137. 'Glossary of terms for mass and volume in analytical chemistry (IUPAC Recommendations 2024)' on page 3 (https://doi.org/10.1515/pac-2023-0903)