 If this is so for every 'cell' of the body, then local thermodynamic equilibrium is said to prevail throughout the body.It makes good sense, for example, to say of the extensive variable , or of the extensive variable , that it has a density per unit volume, or a quantity per unit mass of the system, but it makes no sense to speak of density of temperature per unit volume or quantity of temperature per unit mass of the system.On the other hand, it makes no sense to speak of the internal energy at a point, while when local thermodynamic equilibrium prevails, it makes good sense to speak of the temperature at a point.