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

Keep scrolling for more

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

The underlying law of our universe is entropy, or constant descent into disorder. WSJ, "Modern Heraclitus: Trump’s Genius for Chaos," 1 July 2018 And the expansion, in turn, subjected #MeToo to the familiar physics of American political entropy. Megan Garber, The Atlantic, "Is #MeToo Too Big?," 4 July 2018 On his memorial stone is inscribed his equation, which describes the entropy of a black hole. Laura Yan, Popular Mechanics, "Stephen Hawking's Voice Got Beamed To a Black Hole," 17 June 2018 The stone is also inscribed with one of Hawking's equations describing the entropy of a black hole. NBC News, "Stephen Hawking's ashes buried in Westminster Abbey," 15 June 2018 His music, even since Pavement melted into entropy in 1999, has been jarring and opaque, defined by lyrics that circle around homonyms and puns, or break from generational observations into non sequiturs. Rob Tannenbaum, New York Times, "Stephen Malkmus Doesn’t Think He Was a Jerk," 14 May 2018 In fact, the researchers show that this concept of entropy differences can also be used to identify when a circuit goes beyond the computational power of a classical model. Chris Lee, Ars Technica, "Random quantum circuit easiest way to beat classical computer," 1 May 2018 If the circuit is really just producing noise, as opposed to carrying out an algorithm, then the entropy and energy of the circuit will be different. Chris Lee, Ars Technica, "Random quantum circuit easiest way to beat classical computer," 1 May 2018 The second law of thermodynamics, the strictest of nature’s constraints, says that entropy, a form of disorder, must always increase. The Economist, "Stephen Hawking, one of the world’s great physicists, has died," 14 Mar. 2018

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.

See More

First Known Use of entropy

1868, 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

Keep scrolling for more

Learn More about entropy

Dictionary Entries near entropy

entrepreneuse

entresol

entropion

entropy

entruck

entrust

entry

Statistics for entropy

Last Updated

25 Sep 2018

Look-up Popularity

Time Traveler for entropy

The first known use of entropy was in 1868

See more words from the same year

Keep scrolling for more

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
entropically \-i-k(ə-)lē \ adverb

More from Merriam-Webster on entropy

Britannica English: Translation of entropy for Arabic Speakers

Britannica.com: Encyclopedia article about entropy

Comments on entropy

What made you want to look up entropy? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

required by fashion, etiquette, or custom

Get Word of the Day daily email!

Test Your Vocabulary

Great Scrabble Words—A Quiz

  • scrabble-tiles-that-read-scrabble-quiz
  • Which of the following Q-without-U words means the number five in cards or dice?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!