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Related to Thermodynamic entropy: second law of thermodynamics


1. in thermodynamics, a measure of the part of the internal energy of a system that is unavailable to do work. In any spontaneous process, such as the flow of heat from a hot region to a cold region, entropy always increases.
2. the tendency of a system to move toward randomness.
3. in information theory, the negative of information, a measure of the disorder or randomness in a physical system. The theory of statistical mechanics proves that this concept is equivalent to entropy as defined in thermodynamics.
4. diminished capacity for spontaneous change, as occurs in the psyche in aging.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

en·tro·py (S),

That fraction of heat (energy) content not available for the performance of work, usually because (in a chemical reaction) it has been used to increase the random motion of the atoms or molecules in the system; thus, entropy is a measure of randomness or disorder. Entropy occurs in the Gibbs free energy (G) equation: ΔG = ΔH - TΔSH, change in enthalpy or heat content; T, absolute temperature; ΔS, change in entropy; ΔG, change in Gibbs free energy).
See also: second law of thermodynamics.
[G. entropia, a turning toward]
Farlex Partner Medical Dictionary © Farlex 2012


(S) (en'trŏ-pē)
That fraction of heat (energy) content not available for the performance of work, usually because (in a chemical reaction) it has been used to increase the random motion of the atoms or molecules in the system; thus, a measure of randomness or disorder.
[G. entropia, a turning toward]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


the amount of disorder or the degree of randomness of a system. For example, when a protein is denatured by heat (see DENATURATION), the molecule (which has a definite shape) uncoils and takes up a random shape, producing a large change in entropy.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Therefore, the notion of thermodynamic entropy has also a place in the social systems theoretical apparatus, although in a somewhat different theoretical framework, which brings Pierre Bourdieu's theory of symbolic capital in the theoretical context of meaning developed by Niklas Luhmann, all things considered of course.
Conrad combines thermodynamic entropy at this point with his input of information, where Winnie's transformation is wrought by Verloc's words: "the waves of air of the proper length, propagated in accordance with correct mathematical formulas, flowed around all the inanimate things in the room, lapped against Mrs.
thermodynamic entropy) work better in the opposite direction, as has been seen in the foregoing examples.
But more important, from a functional perspective information is not equivalent either to thermodynamic entropy or "negative entropy" (order).
In this manner, Maxwell suggested, a temperature differential would be created that could be used to do work, thereby reversing the otherwise irreversible thermodynamic entropy. The fundamental problem with this paradigm was that it would be impossible to build and operate a real-world equivalent of a demon at a profit.
For example, the term could be known as thermodynamic entropy, biological entropy, social entropy, and so forth, depending upon where it was applied.
There is skepticism about some biological usage of the entropy concept, such as blurring the distinction between Shannon's entropy and thermodynamic entropy (see Corning and Kline, 1998a, p.
One bit of information, he asserted, is equivalent to `approximately' [10.sup.-23] joules per kelvin: `This is an important figure, the smallest thermodynamic entropy change that can be associated with a measurement yielding one bit of information' (Tribus and McIrvine, 1971, p.
(A more serious objection is that the two forms of entropy are like apples and oranges; thermodynamic entropy has dimensions, whereas informational entropy does not.
In fact, Georgesen-Roegen identifies the advent of the study of thermodynamic entropy with economics.