For black holes, this quantity is equal to one fourth of Boltzmann's constant times surface area, over the Planck length squared.
For black holes, this quantity is equal to one fourth of Boltzmann's constant times surface area, over the Planck length squared. One formula defines it as Boltzmann's constant times the natural logarithm of the number of microstates, and its change was defined as the change in heat over temperature.  The change in Gibbs free energy is equal to enthalpy change minus temperature times change in this quantity.   Measured in joules per Kelvin, FTP, name this quantity which increases according to the Second Law of Thermodynamics, the measure of a system's disorder.
For black holes, this quantity is equal to one fourth of Boltzmann's constant times surface area, over the Planck length squared.
{Entropy} (Prompt on {S})