The specific heat capacity of a material on a per mass basis is $c = \delta C/\delta m$. with $C$ being the heat capacity of a body made of the material and $m$ being the mass of the body. It is the amount of heat required to change the temperature of a mass unit of a substance by one degree. When calculating mass and volume flow in a water heating systems at higher temperature, the specific heat should be corrected.
The sources are: