Specific Heat Capacity
Amount of thermal energy required to raise the temperature of a unit mass of the material by a unit of temperature. Uses units of energy per mass per temperature (most commonly J/kg-K or J/kg-°C, which are fully equivalent).
Specific heat varies with temperature, approaching zero as the temperature of the material approaches absolute zero, and otherwise rising with higher temperature, up until the Debye temperature of the material, when it begins to plateau.
For gases, a distinction is made between specific heat at constant pressure (Cp) and at constant volume (Cv). For solids, this distinction is effectively meaningless.
ASTM testing standards include C1470 (ceramics only), E1269 (differential scanning calorimetry), and E2716 (another variant of differential scanning calorimetry). The only ISO standard as of this writing is 11357-4, which covers plastics.