Entropy

Part of speech: noun

Pronunciation: /ˈɛntɹəpi/

Definitions

1. A quantity that measures the amount of disorder or randomness in a physical or thermodynamic system ; a metric that quantifies the unpredictability or information contained in a message or data source
2. The extent to which components of a system are disorganized, indicating its energy dispersal ; a value expressing the uncertainty and informational content inherent in a signal or communication
3. An indicator of the chaotic arrangement or spread of energy in a system ; a concept describing the level of unpredictability and information density in data transmission

Etymology: Rudolf Clausius, a German physicist, coined "Entropie" in 1865 while working on the second law of thermodynamics. He wanted a term for the part of a system's energy that could not be turned into useful work, and he built it deliberately on "Energie" (energy). He replaced the "érgon" ("work") root of that model with "tropḗ" ("transformation"), so the word means something like "content of transformation." The English form appeared in 1867 as a translation of the German. The word's meaning has since spread far beyond heat engines. Clausius's original sense was physical and measurable, but later physicists, especially Ludwig Boltzmann, tied it to the number of microscopic arrangements a system can take, which is why it came to stand for disorder in general. Today it is used in information theory and everyday speech alike, though the core idea remains the same: the tendency of things to spread out and become less ordered.

Synonyms: disorder, chaos, uncertainty, randomness, instability

Antonyms: order, organization, stability, certainty, structure