What is "disgregation"

Disgregation \Dis`gre*ga"tion\, n. (Physiol.) The process of separation, or the condition of being separate, as of the molecules of a body.

n. 1 Separation; scattering. 2 (context thermodynamics English) entropy, defined as the magnitude of the separation of the particles of a system. Introduced by the German physicist Rudolf Clausius in 1862.

In the history of thermodynamics, disgregation was defined in 1862 by Rudolf Clausius as the magnitude of the degree in which the molecules of a body are separated from each other. This term was modeled on certain passages in French physicist Sadi Carnot's 1824 paper On the Motive Power of Fire that characterized the "transformations" of "working substances" (particles of a thermodynamic system) of an engine cycle, namely "mode of aggregation", which was a precursor to the concept of entropy, which Clausius coined in 1865. It was also a precursor to that of Ludwig Boltzmann's 1870s theories of entropy and order and disorder.