Entropy n. (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. "The entropy of the universe tends towards a maximum."
... condition—in the reverse direction—exists with the transformations of energy. They also are not completely reversible, but tend in a definite direction, from higher- to lower-grade form—unavailable heat energy (the increase of entropy by the second law of thermodynamics). Thus in infinite time the universe should come to a standstill, in spite of the law of conservation of energy, by all energy becoming unavailable for further transformation—that ... — A Book of Exposition • Homer Heath Nugent Read full book for free!