The state postulate is a term used in thermodynamics that defines the given number of properties to a thermodynamic system in a state of equilibrium. The state postulate allows a finite number of properties to be specified in order to fully describe a state of thermodynamic equilibrium. Once the state postulate is given the other unspecified properties must assume certain values. The state postulate is a term used in thermodynamics that defines the given number of properties to a thermodynamic system in a state of equilibrium. The state postulate allows a finite number of properties to be specified in order to fully describe a state of thermodynamic equilibrium. Once the state postulate is given the other unspecified properties must assume certain values.