# entropy

noun
en·​tro·​py | \ ˈen-trə-pē \
plural entropies

## Definition of entropy

1 thermodynamics : a measure of the unavailable energy in a closed thermodynamic system that is also usually considered to be a measure of the system's disorder, that is a property of the system's state, and that varies directly with any reversible change in heat in the system and inversely with the temperature of the system broadly : the degree of disorder or uncertainty in a system
2a : the degradation of the matter and energy in the universe to an ultimate state of inert uniformity Entropy is the general trend of the universe toward death and disorder.— James R. Newman
b : a process of degradation or running down or a trend to disorder The deterioration of copy editing and proof-reading, incidentally, is a token of the cultural entropy that has overtaken us in the postwar years.— John Simon
4 statistical mechanics : a factor or quantity that is a function of the physical state of a mechanical system and is equal to the logarithm of the probability for the occurrence of the particular molecular arrangement in that state
5 communication theory : a measure of the efficiency of a system (such as a code or a language) in transmitting information, being equal to the logarithm of the number of different messages that can be sent by selection from the same set of symbols and thus indicating the degree of initial uncertainty that can be resolved by any one message

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## Other Words from entropy

entropic \ en-​ˈtrō-​pik , -​ˈträ-​pik \ adjective
entropically \ en-​ˈtrō-​pi-​k(ə-​)lē , -​ˈträ-​ \ adverb

## Did You Know?

With its Greek prefix en-, meaning "within", and the trop- root here meaning "change", entropy basically means "change within (a closed system)". The closed system we usually think of when speaking of entropy (especially if we're not physicists) is the entire universe. But entropy applies to closed systems of any size. Entropy is seen when the ice in a glass of water in a warm room melts—that is, as the temperature of everything in the room evens out. In a slightly different type of entropy, a drop of food coloring in that glass of water soon spreads out evenly. However, when a nonphysicist uses the word, he or she is usually trying to describe a large-scale collapse.

## Examples of entropy in a Sentence

Recent Examples on the Web Maxwell had created a system that appeared to defy the rise of entropy, and thus the laws of the universe. These numbers are also fed to a random bit Generator algorithm (RGB) which distills further the entropy of quantum origin to produce random bits in compliancy to NIST 800-90A/B/C standard. The other biggest challenge of working remotely—particularly on a boat—are physics and entropy, says Carey. This expert doom-and-gloomer can’t help but enjoy the tulips finally poking through the soil, the garden fresh and neat and full of promise before the weeds stake their claim and entropy prevails. The congregation may shout or cut a step, and the preacher may peacock a bit to animate the sermon; release can often look like entropy to the untrained eye. Now physicists just had to calculate the entanglement entropy. Some meetings go off without a hitch, but that doesn't mean that entropy won't ensue later. Modularity means minimal variation at each new site, a streamlined design process, and less of the sort of worksite entropy that slows things down.

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'entropy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

## First Known Use of entropy

1867, in the meaning defined at sense 1

## History and Etymology for entropy

International Scientific Vocabulary en- entry 2 + Greek tropē change, literally, turn, from trepein to turn

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Time Traveler for entropy

## The first known use of entropy was in 1867

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## Statistics for entropy

Last Updated

30 Apr 2021

Cite this Entry

“Entropy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/entropy. Accessed 8 May. 2021.

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More Definitions for entropy

entropy

noun
en·​tro·​py | \ ˈen-trə-pē \
plural entropies

## Medical Definition of entropy

: a measure of the unavailable energy in a closed thermodynamic system that is also usually considered to be a measure of the system's disorder and that is a property of the system's state and is related to it in such a manner that a reversible change in heat in the system produces a change in the measure which varies directly with the heat change and inversely with the absolute temperature at which the change takes place broadly : the degree of disorder or uncertainty in a system

Other Words from entropy

entropic \ en-​ˈtrōp-​ik , -​ˈträp-​ \ adjective

More from Merriam-Webster on entropy

Britannica English: Translation of entropy for Arabic Speakers

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