• A metallic element that is important in body functions such as regulation of blood pressure and of water content in cells, transmission of nerve impulses, digestion, muscle contraction, and heartbeat.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• An element with atomic symbol K, atomic number 19, and atomic weight 39.10.
  NCI
  U.S. National Cancer Institute, 2021
• Metallic element of the alkali group, many of whose salts are used in medicine; atomic number 19, symbol K.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Potassium is an electrolyte, which is a mineral in the blood that can be measured by a blood test. Potassium is ingested through food and electrolyte-enhanced beverages and excreted primarily through urine.
  Medscape
  WebMD, 2025