heat capacity, C

Heat brought to a system to increase its temperature divided by that temperature increase. At constant volume C V = ( ∂ U ∂ T ) V at constant pressure C p = ( ∂ H ∂ T ) p, where U is the internal energy and H the enthalpy of the system.
Green Book, 2nd ed., p. 48
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 975