penicillin

noun

pen·​i·​cil·​lin ˌpe-nə-ˈsi-lən How to pronounce penicillin (audio)
1
: any of several relatively nontoxic antibiotic acids of the general formula C9H11N2O4SR that are produced by molds (genus Penicillium and especially P. notatum or P. chrysogenum) or synthetically and are used especially against gram-positive cocci
also : a mixture of such acids
2
: a salt or ester of a penicillin or a mixture of such salts or esters

Examples of penicillin in a Sentence

Recent Examples on the Web Each dose of injectable penicillin can cost hundreds of dollars. Catherine Sweeney, NPR, 26 Feb. 2024 Doctors must find other antibiotic options when treating bacterial infections in patients with penicillin allergies. Erika Edwards, NBC News, 14 Dec. 2023 Ten years later penicillin was found to be a suitable treatment for syphilis. Jasmine Browley, Essence, 8 Feb. 2024 Vials of injectable penicillin in cold storage at the Metro Public Health Department in Nashville, Tenn. Catherine Sweeney, Fortune Well, 2 Feb. 2024 Alexander Fleming extracted the revolutionary antibiotic penicillin from the fungus Penicillium rubens, a discovery that later earned him the Nobel Prize in Medicine. Gabe Allen, Discover Magazine, 28 Nov. 2023 Getty Images Bloomberg—US regulators gave temporary permission for importation of a form of penicillin used to treat syphilis amid a national shortage of Pfizer Inc.’s version of the drug along with a dramatic increase in cases. Ike Swetlitz, Fortune Well, 10 Jan. 2024 Almost all are resistant to multiple antibiotics, including penicillin, ampicillin, amoxicillin, ticarcillin, carbenicillin, and cephalothin. Ashley Belanger, Ars Technica, 1 Sep. 2023 People who are allergic to penicillin may also have higher odds, adds David Colombo, MD, director of maternal-fetal medicine at Spectrum Health in Michigan. Nicole Harris, Parents, 14 Jan. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'penicillin.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin Penicillium

First Known Use

1929, in the meaning defined at sense 1

Time Traveler
The first known use of penicillin was in 1929

Dictionary Entries Near penicillin

Cite this Entry

“Penicillin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/penicillin. Accessed 19 Mar. 2024.

Kids Definition

penicillin

noun
pen·​i·​cil·​lin ˌpen-ə-ˈsil-ən How to pronounce penicillin (audio)
: any of several antibiotics or a mixture of these produced by penicillia or in the laboratory and used especially against round disease-producing bacteria
Etymology

from scientific Latin Penicillium "a genus of molds producing antibiotics," from Latin penicillus, literally, "little tail" — related to pencil

Medical Definition

penicillin

noun
pen·​i·​cil·​lin ˌpen-ə-ˈsil-ən How to pronounce penicillin (audio)
1
: a mixture of relatively nontoxic antibiotic acids produced especially by molds of the genus Penicillium (as P. notatum or P. chrysogenum) and having a powerful bacteriostatic effect against various chiefly gram-positive bacteria (as staphylococci, gonococci, pneumococci, hemolytic streptococci, or some meningococci)
2
: any of numerous often hygroscopic and unstable amido acids (as penicillin G, penicillin O, and penicillin V) that have a structure in which a four-membered lactam ring shares a nitrogen and a carbon atom with a thiazolidine ring to which it is fused and that are components of the penicillin mixture or are produced biosynthetically by the use of different strains of molds or different media or are synthesized chemically
3
: a salt or ester of a penicillin acid or a mixture of such salts or esters

More from Merriam-Webster on penicillin

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