Boltzmann constant

The Boltzmann constant ("k" or "k"B) is a physical constant. It is defined to be J/K. It relates the average kinetic energy of a particle in a gas with the temperature of the gas. It is the gas constant "R" divided by the Avogadro constant "N"A:
The Boltzmann constant has SI units of J⋅K−1 (also written J/K), the same as entropy. It is named after the Austrian physicist Ludwig Boltzmann.