Specific quantity
In the natural sciences, including physiology and engineering, a specific quantity generally refers to an intensive quantity obtained by dividing an extensive quantity of interest by mass. If the divisor quantity is named, the name is usually placed before "specific" in the term (i.e., thrust specific fuel consumption). Named and unnamed divisor quantities are given for the terms below. Mass-specific quantities. Per unit of mass (short form of "mass-specific"): Other specific quantities. Per unit of other type. The dividing unit is sometimes added before the term "specific", and sometimes omitted.