Density 32 : The weight of a substance per unit of volume. For instance, the density of a drilling mud may be described as "10 lb. per gallon" or 75 lb. per cubic foot". (ITOGP)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}