Zeroth law of thermodynamics: Introduction of temperature as a basic physical quantity: If two systems are each in thermodynamic equilibrium with a third, they are also in equilibrium with each other. The state variable that coincides for these systems is the temperature.
First law of thermodynamics: The energy of a closed system is constant.
Second law of thermodynamics: Thermal energy cannot be converted into other types of energy to any desired extent.
Third law of thermodynamics: (Nernst theorem): Absolute zero temperature is unattainable.