boric acid

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A water-soluble white or colorless crystalline compound, H₃BO₃, used as an antiseptic and preservative and in fireproofing compounds, cosmetics, ophthalmic solutions, cements, and enamels.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry 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.
• noun chemistry A hydrate of boric oxide, specifically any of the three acids orthoboric acid, metaboric acid, or pyroboric acid.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of various acids containing boron and oxygen
• noun a white or colorless slightly acid solid that is soluble in water and ethanol; used in the manufacture of glass and paper and adhesives and in detergents and as a flux in welding; also used as an antiseptic and food preservative