- potassium, K, atomic number 19 - a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite
--1 is a kind of metallic element, metal
--1 is a substance ofseawater, saltwater, brine; carnallite; kainite; langbeinite; sylvite, sylvine