enthalpy, heat content, total heat, H - (thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure; "enthalpy is the amount of energy in a system capable of doing mechanical work"

randomness, entropy, S - (thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work; "entropy increases as matter and energy in the universe degrade to an ultimate state of inert uniformity"

natural philosophy, physical science, physics - the science of matter and energy and their interactions

thermodynamics of equilibrium, thermostatics - the aspect of thermodynamics concerned with thermal equilibrium

adiabatic process - (thermodynamics) any process that occurs without gain or loss of heat

cyclic - conforming to the Carnot cycle