Entropy
Etymology
Coined in 1865 by the physicist Rudolf Clausius from Greek en-, "in," plus trope, "transformation, turning." He deliberately shaped the word to echo "energy," since the two quantities were partners in his thermodynamics. It later spread far beyond physics — to information theory and everyday talk of things falling apart — sometimes loosely.
noun · /EN-truh-pee/
A measure of disorder in a system, and the tendency of things to drift toward disorder over time.
What it names
The relentless slide of organized systems toward randomness and evenness — why order takes effort to maintain and decay comes for free.
Example
Left untended, the shared codebase succumbed to entropy, each quick fix adding a little more tangle.
Related idea
Decay is the visible ruin of a particular thing; entropy is the general physical principle underneath it, a quantified tendency toward disorder rather than a single rotting object.