1. The ratio of the mass of any substance to the volume occupied by it (usually expressed in kilograms per cubic meter, but any other unit system may be used); the reciprocal of specific volume.
The density of a unit of water after it is raised by an adiabatic process to the surface, i.e., determined from in-situ salinity and potential temperature (AGI, 1980). Density that would be reached by a compressible fluid if it were adiabatically compressed or expanded to a standard pressure.
The vertical integral of the density of absorbers between two altitudes; used mainly in determining the transmission through an absorbing gas.