soda ash

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

• noun Sodium carbonate in powdery white form, used especially as an industrial chemical.

from The Century Dictionary.

• noun The trade-name of sodium carbonate. See soda.

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

• noun industrial-grade sodium carbonate

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

• noun a sodium salt of carbonic acid; used in making soap powders and glass and paper