potassium

potassium — noun

1. a metal element with a soft, silver-white appearance that is usually found joine

1.nounC1
Definition

a metal element with a soft, silver-white appearance that is usually found joined to other elements and helps make things such as fertilizer, soap, and glass.

Example

Pure potassium stays under oil so it does not react too quickly.

pure potassium under oil

Potassium burned brightly when the teacher dropped a tiny piece into water.

potassium reacts with water

Common collocations
  • potassium reacts with water
  • pure potassium
  • potassium compounds
Synonyms
  • K

    the chemical symbol, used in formulas, charts, and labels rather than ordinary explanation

  • potash

    often refers to potassium compounds, especially in farming or industry, so it is less exact than the element name

  • potassium metal

    a narrower term for the pure reactive form

Grammar Patterns

potassium reacts with water

potassium compounds

add potassium to soil

pure potassium under oil

Usage Note

Usually uncountable. In many contexts, speakers mean potassium as part of compounds or materials rather than a piece of the pure metal.

Common Mistakes

A potassium reacts with water very fast.
Potassium reacts with water very fast.
names of chemical elements are usually uncountable when you mean the substance.

Synonym discussion

Sense: noun/1

'Potassium' is the normal word for the chemical element itself. 'K' is only the symbol, so it fits charts, formulas, and labels more than everyday explanation. 'Potash' is older and less exact in modern English; it often means potassium compounds used in farming or industry, not the pure element. 'Potassium metal' is narrower, because it points to the pure reactive form that scientists handle carefully. 'Potassium chloride' is not another name for potassium at all, but one specific compound that contains it. Use 'potassium' when you mean the element in general, but switch to the more exact term when the context is a formula, a compound, or a lab demonstration. A teacher may write K on the board, then explain that the jar contains potassium metal.

Kpotashpotassium metalpotassium chloride

Common collocations

Nouns

  • potassium compound
  • potassium metal
  • potassium fertilizer

Phrases

  • add potassium to soil
  • keep potassium under oil
  • potassium reacts with water

Prepositions

  • potassium in compounds
  • potassium in soil

Etymology

EnglishNew LatinEnglish

The name was formed in scientific Latin from the English word 'potash' and the ending '-ium', which became common in names of elements. English then took the new form back as 'potassium'.