Entropy

The entropy, S, is defined by

$S=k_{B}\ln \Omega$

where $k_{B}$ is the Boltzmann constant and $\Omega$ (sometimes written as Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle W} ) is the number of microscopic configurations that result in the observed macroscopic description of the thermodynamic system.

See also:

• Entropy of a glass
• Shannon entropy
• Tsallis entropy