Definition of "sulfurous acid" []

• A colorless solution of sulfur dioxide in water, H2SO3, characterized by a suffocating sulfurous odor, used as a bleaching agent, preservative, and disinfectant. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.