Equilibrium
Etymology
From Latin aequilibrium, joining aequus ("equal") and libra ("balance, scales") — literally "equal balance," the image of a scale whose pans hang level. It entered physics for balanced forces and was later borrowed by chemistry, economics, and ecology for any system whose opposing tendencies offset each other.
noun · /ee-kwuh-LIB-ree-um/
A state in which the forces or flows acting on a system balance out, so it stops changing overall even if activity continues underneath.
What it names
The resting point a situation settles into once competing pressures cancel — and why nudging just one side rarely moves things until the whole balance shifts.
Example
Their household chores reached a quiet equilibrium where no one felt they were doing more than their share.
Related idea
Homeostasis is equilibrium that actively defends itself. A dead battery sits at equilibrium; a living body spends energy to hold its balance in place.