New Latin, from potassa potash, from English potash
First Known Use: circa 1807
Medical Definition of POTASSIUM
: a silver-white soft light low-melting monovalent metallic element of the alkali metal group that occurs abundantly in nature especially combined in minerals—symbol K; see element table
Chemical element, one of the alkali metals, chemical symbol K, atomic number 19. It is a soft, silvery white metal, not found free in nature and rarely used as the metal (except as a chemical reagent) because of its extreme reactivity. Potassium is essential for life and is present in all soils. Potassium ions (K+) and sodium ions act at cell membranes in electrochemical impulse transmission and in transport. Potassium in compounds has valence 1. The chloride is used as a fertilizer and a raw material for producing other compounds, and the hydroxide for making liquid soaps and detergents and in preparing various salts. The iodide is added to table salt to protect against iodine deficiency. The nitrate is also called saltpetre, and the carbonate is called potash.