[ am-puh-sil-in ]
See synonyms for ampicillin on
  1. a broad-spectrum semisynthetic penicillin, C16H19N3O4S, effective against certain susceptible Gram-positive and Gram-negative bacteria.

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Origin of ampicillin

First recorded in 1965–70; probably am(inobenzyl)p(en)icillin, an alternate chemical name

Words Nearby ampicillin Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

British Dictionary definitions for ampicillin


/ (ˌæmpɪˈsɪlɪn) /

  1. a semisynthetic penicillin used to treat various infections

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for ampicillin


[ ăm′pĭ-sĭlĭn ]

  1. An antibiotic derived from penicillin that has a broad antibacterial spectrum of action. It is effective against gram-negative and gram-positive bacteria and is used primarily to treat gonorrhea and infections of the respiratory, urinary, and intestinal tracts.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.