ENGLISH
REFERENCE

potassium

n.
US //pəˈtæsiəm// UK //pətˈæsiəm// potas·si·um
  1. 1 chemical element (n.)
    B2 Upper Intermediate Technical Science

    a soft, silver-colored metal that reacts very quickly with water and air.

    a soft, silvery-white alkali metal, atomic number 19, that is highly reactive and never found in its pure state in nature.

    Example

    In chemistry class, the teacher showed us how potassium reacts when dropped into water.

    Example

    Potassium is so reactive that it must be stored under mineral oil to prevent it from oxidizing in the air.

    Usage

    Uncountable when referring to the element in general.
    • k
  2. 2 dietary mineral (n.)
    B2 Upper Intermediate Medicine

    a mineral found in food that helps your heart and muscles work correctly.

    an essential dietary mineral and electrolyte that facilitates nerve impulses and maintains cellular fluid balance.

    Example

    Bananas and potatoes are excellent sources of potassium for a healthy diet.

    Example

    The patient was advised to increase their intake of potassium to help manage their blood pressure naturally.

    Usage

    Uncountable in a nutritional context.
Origin

Coined by British chemist Humphry Davy in 1807, from potassa (a Latinized form of potash) + -ium.

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

Last updated June 20, 2026