ENGLISH
REFERENCE

lithium

n.
US //ˈɫɪθiəm// UK //lˈɪθiəm// lithi·um
  1. 1 chemical element (n.)
    B2 Upper Intermediate Technical Science

    a very light, soft, silver-coloured metal that is a chemical element.

    the lightest solid chemical element, an alkali metal with atomic number 3. Uncountable in its elemental sense.

    Example

    Lithium is a very reactive metal that must be stored in oil to prevent it from reacting with air.

    Example

    As the lightest of all metals, lithium possesses a high electrochemical potential, making it an ideal component for high-energy-density applications.
    • li
  2. 2 battery technology (n.)
    B2 Upper Intermediate Computing

    the material used inside rechargeable batteries for phones, laptops, and electric cars.

    the active material in high-capacity rechargeable batteries. Often used attributively in 'lithium-ion'.

    Example

    Most modern smartphones use lithium batteries because they last a long time and are very light.

    Example

    The global demand for lithium has surged alongside the rapid expansion of the electric vehicle market and renewable energy storage solutions.
    • lithium ion
  3. 3 medicine (n.)
    C1 Advanced Technical Medicine

    a drug used by doctors to treat certain mental health conditions, like bipolar disorder.

    lithium carbonate or other lithium salts administered as a psychiatric medication to stabilise mood. Uncountable when referring to the medication.

    Example

    The doctor prescribed lithium to help balance his mood and prevent episodes of depression.

    Example

    Patients prescribed lithium require regular blood tests to ensure the drug remains within a narrow therapeutic range and to monitor kidney function.

    Usage

    Usually refers to lithium carbonate in a medical context.
    • mood stabiliser
Origin

From New Latin lithium, from Ancient Greek λίθος (líthos, “stone”) + -ium.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Last updated June 20, 2026