When we talk about thermal mass, we usually refer to the ability of certain materials to store and release heat energy. However, there are other terms that can be used as synonyms, depending on the context. One possible term is heat capacity, which describes the amount of heat required to raise the temperature of a substance by a certain amount. Another term is specific heat, which is the amount of heat required to raise the temperature of a substance by one degree. Thermal inertia is also used to describe the tendency of a material to resist changes in temperature. Ultimately, these terms all refer to the same concept, which is the ability of a substance to regulate its temperature based on its capacity to store and release heat.