- sodium, Na, atomic number 11 - a silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in sea water and in the mineral halite (rock salt)
--1 is a kind of metallic element, metal
--1 is a substance of seawater, saltwater, brine; halite, rock salt