English Reference
noun

sodium

n.
US /ˈsoʊdiəm/ UK /sˈəʊdiəm/ sodi·um UK spelling sodiums

  1. 01 B2 Upper Intermediate Technical Science

    a soft, silver-white metal that reacts strongly with water and is never found alone in nature.

    the chemical element with atomic number 11; a soft, silvery-white alkali metal that is highly reactive and occurs naturally only in compounds.

    Simple

    Pure sodium is so soft that you can cut it with a kitchen knife.

    In context

    The chemist demonstrated how pure sodium reacts violently when exposed to water, producing hydrogen gas and a strong alkaline solution.

    Usage

    Uncountable in its chemical sense.

    na
  2. 02 B2 Upper Intermediate Medicine

    the part of salt that can affect your health; often used when talking about food and diet.

    the sodium content found in food, typically as a component of sodium chloride (table salt).

    Simple

    The doctor told him to eat less sodium to help lower his blood pressure.

    In context

    Processed foods often contain high levels of hidden sodium, which can contribute to hypertension if consumed in excessive quantities over time.

Another gene known as SGK1, which affects the kidneys’ ability to hold onto sodium (salt), also became less active.

ScienceDaily· 13 Aug 2026

Coined by British chemist Humphry Davy in 1808, from soda + -ium.

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

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated