Definition of "sulfonamide" []

• Any of a group of organic sulfur compounds containing the radical SO2NH2 and including the sulfa drugs. (noun)
• See sulfa drug. (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.

• "The 2011 version turns out to be resistant to eight classes of antibiotics, including penicillin, streptomycin and sulfonamide."
• "It turned out I had a violent allergic reaction to this sulfonamide drug."
• "She was not convinced the drug was to blame, but she agreed to authorize a different prescription—a sulfonamide, a drug class that has been on the market even longer than penicillin."