boric acid noun2 •H₃BO₃; B(OH)₃; a white crystalline solid, soluble in hot water to form a weak acid. Used as a mild antiseptic, flame retardant, insecticide, and in the manufacture of borax and other borate salts. •A hydrate of boric oxide, specifically any of the three acids orthoboric acid, metaboric acid, or pyroboric acid. formsboric acids
