Mass density

Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D (or d) can also be used: \rho = \frac{m}{V}, where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate this quantity is more specifically called specific weight.

ratio of the density (mass per volume) of a substance to the density of a given reference material

mass per unit volume of earths atmosphere

amount of bone mineral in bone tissue

mass density of a component in a chemical mixture

overall density of a granular material, with void space included in the denominator

the density of a two-dimensional object, or of the surface of a three-dimensional object, calculated as the mass per area

gas used to create buoyancy in a balloon or aerostat

a state where buoyancy forces are exactly balanced by weight on an immersed body

density of individual particles contained in a granular material or other heterogeneous mixture

density of the nucleus of an atom