Heat generation rate ($\dot{Q}$)

Thermal energy generated per unit time, often specified per volume as $q^{\prime \prime \prime }$ in $\mathrm{W}{\mathrm{m}}^{-3}$. Integrating a volumetric source over a region gives its total thermal power.

Thermal power generated per unit volume. Its integral over a region is the region's total heat generation rate.