Entropy
The Second Law of Thermodynamics
A measure of disorder or randomness in a system. In any closed system, things naturally drift from order toward disorder over time — which is why so many everyday processes are easy to start but impossible to reverse.
EverydayConcepts.io
Origin
German physicist Rudolf Clausius coined the term in 1865, deliberately choosing a word derived from the Greek entropia ("transformation") to echo the word "energy." Clausius had first articulated the underlying principle — what became the second law of thermodynamics — in his 1850 paper "On the Moving Force of Heat," but it took fifteen more years to give the idea its lasting name.
Updated February 22, 2026