Definition

1. Noun:
   • A state of balance between opposing forces or actions: A condition in which different elements are equal or in correct proportions, resulting in stability.
   • A state of physical balance: The state of a body at rest or in uniform motion where the resultant of all forces acting upon it is zero.
   • Mental or emotional stability: A calm state of mind where one is not unduly affected by emotions.
   • The state of a chemical reaction where the forward and reverse reactions occur at the same rate: The concentrations of reactants and products remain constant over time.

Examples of Usage

• Noun:
  • The scales are in equilibrium. (The weights on both sides are equal, so the scale is balanced.)
  • She struggled to maintain her emotional equilibrium after the news. (She tried to keep her feelings stable and calm.)
  • The market reached an equilibrium where supply equaled demand. (The amount of goods available was the same as the amount people wanted to buy.)
  • In this chemical equilibrium, the amount of product formed is constant. (The reaction is balanced, so the product concentration doesn't change.)

Advanced Usage

• "Dynamic equilibrium": A state of balance in a system where processes are ongoing but their effects cancel each other out, resulting in no net change.
  • The population of the species is in dynamic equilibrium, with birth and death rates being equal.
• "Thermodynamic equilibrium": The condition of a system in which all macroscopic flows are zero; the state variables (temperature, pressure) do not change over time.
  • The coffee cup and the room air will eventually reach thermodynamic equilibrium.
• "Nash equilibrium" (in game theory): A stable state in a strategic interaction where no participant can gain by unilaterally changing their strategy.
  • In the prisoner's dilemma, both prisoners confessing is a Nash equilibrium.

Variants and Related Words

• Equilibrist (noun): An acrobat who performs balancing feats.
• Equilibrate (verb): To bring into or keep in equilibrium.
  • The system will eventually equilibrate.
• Disequilibrium (noun): A loss or lack of equilibrium or stability.
  • The sudden economic shock caused a period of disequilibrium.

Synonyms

• Balance: A state of equilibrium or equipoise.
• Stability: The state of being stable; resistance to change or disruption.
• Poise: A state of balance or equilibrium, often referring to composure.
• Steadiness: The quality of being steady, not shaking or moving.

Related Phrases

• "Sense of equilibrium": Refers specifically to the bodily sense of balance, governed by the vestibular system in the inner ear.
  • An ear infection can disrupt your sense of equilibrium.
• "Equilibrium constant (Keq)": In chemistry, the ratio of product concentrations to reactant concentrations at equilibrium.
  • A large equilibrium constant favors product formation.
• "Equilibrium price": In economics, the price at which the quantity of a good demanded equals the quantity supplied.
  • The auction helped discover the equilibrium price for the rare painting.

Related Idioms

• "Tip the balance/equilibrium": To cause a change in a situation that was previously balanced.
  • The new evidence tipped the equilibrium in favor of the defendant.
• "Off balance/equilibrium": In a state of physical unsteadiness or mental confusion.
  • The sudden question caught him off equilibrium.

Noun

1. a sensory system located in structures of the inner ear that registers the orientation of the head
2. equality of distribution
3. a chemical reaction and its reverse proceed at equal rates
4. a stable situation in which forces cancel one another