ˈsōdēəm noun
( -s )
Etymology: New Latin, from English soda + New Latin -ium
: a silver white soft waxy ductile metallic element of the alkali metal group that has a low melting point and density and high electrical and thermal conductivity, that occurs abundantly in nature in combined form (as rock salt, Chile saltpeter, trona, borax, glauberite, albite), in soils, in the sea and other salt waters, in most plants, and in the animal body especially in the fluids, that is usually prepared by electrolysis of a mixture of fused sodium chloride and calcium chloride, that is very active chemically and oxidizes and tarnishes readily in air and burns with a yellow flame, that reacts violently with water to form sodium hydroxide and spontaneously ignitable hydrogen, that is stored under kerosene, other inert hydrocarbon liquid, or in tight containers protected from moisture and air, and that is used sometimes in the form of its amalgam or other alloys or in dispersions in hydrocarbon liquids in making tetraethyl lead and various sodium compounds (as sodium cyanide, sodium hydride, sodium peroxide), in organic synthesis (as in reducing esters to alcohols for making detergents), in metallurgy especially for removing oxygen or various impurities, in sodium-vapor lamps, and as a heat-transfer agent especially in cooling valves for internal-combustion engines — symbol Na ; see element table; compare radiosodium