|Definition:|| at a given point within a three-dimensional domain of quasi-infinitesimal volume dV, scalar quantity equal to the mass dm within the domain divided by the volume dV, thus ρ = dm/dV|
NOTE 1 Mass density is an intensive quantity describing a local property of a substance.
NOTE 2 The concept of mass density may also be applied to the mass m in a domain D with volume V, leading to the average density .
NOTE 3 The coherent SI unit of mass density is kilogram per cubic metre, kg/m3. Other units are tonne per cubic metre, t/m3 (1 t/m3 = 1 000 kg/m3 = 1 g/cm3), and kilogram per litre, kg/l (1 kg/l = 1 000 kg/m3).