Other forms: equilibria
Equilibrium is the state in which opposing forces balance exactly, so nothing changes. A set of scales at rest, a chemical reaction going both ways at the same rate, an economy where supply meets demand.
It is a technical word first and a figurative one second, and both are common. In physics and chemistry it has a strict definition; in economics it names the price at which a market clears; in ordinary speech it means composure — she recovered her equilibrium — which is a rather formal way to say it. The plural is equilibria, and the adjective is the awkward equilibrial, which almost nobody uses. Note that equilibrium is not the same as stillness: a thing in dynamic equilibrium is busy, and simply not changing overall.
1nounequilibriumA state in which opposing forces or influences are balanced.
“The system reaches equilibrium after about an hour.”
2nouncalmA calm and settled state of mind.
“It took her a minute to recover her equilibrium.”
3nouneconomicsIn economics, the price or level at which supply and demand match.
“The market settled at a new equilibrium.”
equilibrium is a state of balance.
equiLIBRium → a LIBRARY shelf that does not tip
A library shelf with the same weight at each end, so nothing tips over.
hooks ontolibrary
Latin aequilibrium is aequus, equal, plus libra, a balance or pair of scales — the same libra that gave the pound its abbreviation lb and the zodiac its Libra. The word is a picture of a beam balance with nothing tipping it.
Latin
aequilībrium
English, today
equilibrium
Built from
From Latin aequilībrium, from aequus + lībra (“balance”).
Etymology from Wiktionary, CC BY-SA