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equilibrium

n.
US //ˌikwəˈɫɪbɹiəm// UK //ˌiːkwɪlˈɪbɹiəm// equi·lib·ri·um
  1. 1 physical or general balance (n.)
    C1 Advanced Academic Science

    a state where different parts or forces are balanced and stable.

    a condition in which all acting influences are cancelled by others, resulting in a stable, balanced, or unchanging system.

    Example

    The scales reached equilibrium when the weights on both sides were exactly the same.

    Example

    The ecosystem maintained a delicate equilibrium for centuries until the introduction of invasive species disrupted the local food chain.

    Usage

    Often used with the verbs 'maintain', 'disturb', or 'restore'.

  2. 2 chemical balance (n.)
    C1 Advanced Technical Science

    the point in a chemical reaction where the forward and backward changes happen at the same speed.

    the state of a reversible chemical reaction in which the rates of the forward and reverse reactions are equal, resulting in no net change in concentrations.

    Example

    In a closed bottle of soda, the liquid and gas reach equilibrium.

    Example

    The chemist adjusted the temperature to shift the equilibrium of the reaction, thereby increasing the yield of the desired product.

    • chemical balance
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  1. 3 mental calmness (n.)
    C2 Proficiency Formal Literary

    a calm state of mind where you feel balanced and in control.

    a state of emotional or mental balance; composure.

    Example

    Yoga helps her recover her equilibrium after a stressful day at the office.

    Example

    It took several months of quiet reflection for him to regain his mental equilibrium following the sudden collapse of his business empire.

Origin

From Latin aequilībrium, from equal + lībra (“balance”).

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