Entropy

n. [ Gr. &unr_; a turning in; &unr_; in + &unr_; a turn, fr. &unr_; to turn. ] (Thermodynamics) A certain property of a body, expressed as a measurable quantity, such that when there is no communication of heat the quantity remains constant, but when heat enters or leaves the body the quantity increases or diminishes. If a small amount, h, of heat enters the body when its temperature is t in the thermodynamic scale the entropy of the body is increased by h ÷ t. The entropy is regarded as measured from some standard temperature and pressure. Sometimes called the thermodynamic function. [ 1913 Webster ]

The entropy of the universe tends towards a maximum. Clausius. [ 1913 Webster ]