equi·​lib·​ri·​um | \ˌē-kwə-ˈli-brē-əm, ˌe-\
plural equilibriums or equilibria\ ˌē-​kwə-​ˈli-​brē-​ə , ˌe-​ \

Definition of equilibrium 

1a : 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)

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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.

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

In the year since then, an equilibrium of sorts has held. Andrew Prokop, Vox, "Why Trump hasn’t tried to pardon his way out of the Mueller probe — yet," 1 June 2018 But longer dry seasons, the expansion of the desert and one of the world’s fastest-growing populations, has destroyed that equilibrium. Joe Parkinson, WSJ, "Dwindling Farmland Sparks a Deadly Conflict in Nigeria," 27 May 2018 The effect of the injury upon the man seems to have been the destruction of the equilibrium between his intellectual faculties and the animal propensities. Daniel C. Schlenoff, Scientific American, "“Foul Treachery” of Trotsky and Lenin in 1918; Phineas Gage’s Brain in 1868," 13 July 2018 One dose of compost ignited what Silver calls a state change: The plants and the soil — and everything that inhabited it — moved toward a new equilibrium in which the soil ecosystem pulled in and retained greater amounts of carbon. Moises Velasquez-manoff, New York Times, "Can Dirt Save the Earth?," 18 Apr. 2018 With the market moving toward equilibrium and bloated inventories shrinking, the next step for global producers will be to phase out the reductions, Khalid Al-Falih told reporters in New Delhi on Saturday. Debjit Chakraborty, Bloomberg.com, "Saudis See Oil Output Cuts Easing in 2019," 24 Feb. 2018 The spoon shook, tipping toward the handle end, and Morris Melnik quickly poured a little salt into the bowl of the spoon to give it equilibrium. Ben Taub, The New Yorker, "The Boarder," 30 Apr. 2018 On a recent four-game winning streak, the Dodgers (8-9) regained some equilibrium. Andy Mccullough, latimes.com, "After another blown save, Dodgers closer Kenley Jansen still searching for answers," 19 Apr. 2018 The baleful equilibrium is punctuated, when control of the various branches aligns, by spurts of partisan lawmaking. The Economist, "America’s electoral system gives the Republicans advantages over Democrats," 12 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'equilibrium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of equilibrium

1608, in the meaning defined at sense 1a

History and Etymology for equilibrium

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

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Last Updated

5 Nov 2018

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Time Traveler for equilibrium

The first known use of equilibrium was in 1608

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More Definitions for equilibrium



English Language Learners Definition of equilibrium

: a state in which opposing forces or actions are balanced so that one is not stronger or greater than the other

: a state of emotional balance or calmness


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

Kids Definition of equilibrium

1 : a state of balance between opposing forces or actions

2 : the normal balanced state of the body that is maintained by the inner ear and that keeps a person or animal from falling


equi·​lib·​ri·​um | \ˌē-kwə-ˈlib-rē-əm, ˌek-wə- \
plural equilibriums or equilibria\ -​rē-​ə \

Medical Definition of equilibrium 

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

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