equilibrium

noun

equi·​lib·​ri·​um ˌē-kwə-ˈli-brē-əm  ˌe- 

plural equilibriums or equilibria ˌē-kwə-ˈli-brē-ə 

ˌe-

1

a

: a state of intellectual or emotional balance : poise

trying to recover his equilibrium

b

: a state of adjustment between opposing or divergent influences or elements

2

: a state of balance between opposing forces or actions that is either static (as in a body acted on by forces whose resultant is zero) or dynamic (as in a reversible chemical reaction when the rates of reaction in both directions are equal)

3

: balance sense 3a

Did you know?

Equilibrium contains a root from the Latin libra, meaning "weight" or "balance". As a constellation, zodiac symbol, and astrological sign, Libra is usually pictured as a set of balance scales, often held by the blindfolded goddess of justice, which symbolizes fairness, equality, and justice. Equilibrium has special meanings in biology, chemistry, physics, and economics, but in all of them it refers to the balance of competing influences.

Synonyms

• balance
• counterpoise
• equilibration
• equipoise
• poise
• stasis

Examples of equilibrium in a Sentence

Supply and demand were in equilibrium.

we must find an equilibrium between commercial development and conservation of our natural treasures

Recent Examples on the Web

Practice intentionally throwing yourself off balance a little bit so your body must work to find its equilibrium again. —Jessica Dulong, CNN Money, 20 June 2025

Malaysia’s chairmanship helped maintain this equilibrium by avoiding escalatory language while keeping diplomatic channels to Beijing open. —Benjamin Laker, Forbes.com, 19 June 2025

Every feeling and its opposite are readily available to either partner, so that even a slight disruption of their equilibrium can result in wild swings toward loathing. —Jesse Green, New York Times, 19 May 2025

If the regime gets its way over the next three to four years, Russia could arrive at a sociopolitical equilibrium that looks less like a capitalist authoritarian country with private-sector elites and more like a North Korean–style militarized autocracy. —Andrei Yakovlev, Foreign Affairs, 16 May 2025

Word History

Etymology

Latin aequilibrium, from aequilibris being in equilibrium, from aequi- + libra weight, balance

First Known Use

1608, in the meaning defined at sense 1a

Phrases Containing equilibrium

• equilibrium constant
• punctuated equilibrium

Rhymes for equilibrium

• disequilibrium
• nonequilibrium

Kids Definition

equilibrium

noun

equi·​lib·​ri·​um ˌē-kwə-ˈlib-rē-əm 

ˌek-wə-

plural equilibriums or equilibria -rē-ə 

1

: a state of balance between opposing forces or actions

2

: the normal balanced state of the body of an animal that is maintained in relation to the forces (as gravity) acting on it and to things in the environment (as the surface on which life is lived) and that is sensed and checked by the inner ear of vertebrates including human beings

Etymology

from Latin aequilibrium "state of being in balance," from aequus "equal" and libra "weight, balance, scales" — related to deliberate, libra

Medical Definition

equilibrium

noun

equi·​lib·​ri·​um ˌē-kwə-ˈlib-rē-əm  ˌek-wə- 

plural equilibriums or equilibria -rē-ə 

1

: a state of balance between opposing forces or actions that is either static (as in a body acted on by forces whose resultant is zero) or dynamic (as in a reversible chemical reaction when the velocities in both directions are equal)

2

: a state of intellectual or emotional balance