English Reference

Word

entropy

Phoneticsen·tropy

US/ˈɛntɹəpi/

UK/ˈɛntɹəpi/

Definitions

01scientific disorder

C1 · Science

n. a scientific measurement of how much energy is spread out or how messy a system is.

n. A thermodynamic property representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder.

“In physics, the law of entropy says that the universe is slowly becoming more disordered.”

“The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time.”

Technical

Usage

Uncountable in general scientific contexts; countable when referring to specific mathematical values.

02general decline into chaos

C2

n. the natural way that things become disorganized or fall apart if you do not look after them.

n. The inevitable and steady deterioration of a system or society; a metaphorical extension of the thermodynamic principle to social or organizational contexts.

“Without a manager to lead the team, the project quickly fell into entropy.”

“The essay argues that the political entropy of the late empire was caused by a lack of central communication and crumbling infrastructure.”

Academic · Literary

Antonyms

03information theory

C2 · Computing

n. a measure of how much information or 'noise' is in a signal or message.

n. A mathematical measure of the uncertainty or information content associated with a random variable or data stream.

“The software uses entropy to create truly random passwords that are hard to guess.”

“High entropy in a data set indicates a high degree of unpredictability, which is essential for robust cryptographic applications.”

Technical

Synonyms

uncertaintyinformation density

Real-World Examples

“Instead of simply guessing words packed with common letters or choosing the most likely answer, the method uses Shannon entropy, a measure from information theory, to identify guesses that reveal the most useful information.”
ScienceDaily · 12 Sept 2026
“The key to it all is entropy: “this universe moves toward the Big Bang, and entropy is reversed,” Eli explains.”
The Guardian · 1 Sept 2026

Etymology

First attested in 1867, as the translation of German Entropie, coined in 1865 by Rudolph Clausius in analogy to Energie (“energy”), replacing the root of Ancient Greek ἔργον (érgon, “work”) by Ancient Greek τροπή (tropḗ, “transformation”)).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

entropicAdjectiveentropyNoun

Domain

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This entry

Level
C2 · Proficiency
Frequency
Frequent
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