hydrochloric acid

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

• noun A clear, colorless, fuming, poisonous, highly acidic aqueous solution of hydrogen chloride, HCl, used as a chemical intermediate and in petroleum production, ore reduction, food processing, pickling, and metal cleaning. It is found in the stomach.

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

• noun inorganic chemistry A strong acid made by dissolving the gas, hydrogen chloride, in water. It reacts with alkalis, bases and many metals to form chlorides; it has many industrial applications.

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

• noun an aqueous solution of hydrogen chloride; a strongly corrosive acid