bac·​te·​ri·​o·​phage bak-ˈtir-ē-ə-ˌfāj How to pronounce bacteriophage (audio)
-ˌfäzh How to pronounce bacteriophage (audio)
plural bacteriophages
: a virus that infects bacteria : phage
Much smaller than the bacteria they attack, bacteriophages cannot grow and multiply on their own.C. Claiborne Ray
The genes were amplified by using PCR [=polymerase chain reaction] and inserted into … a bacteriophage of E. coli.Ricki Lewis
bacteriophagy noun

Examples of bacteriophage in a Sentence

Recent Examples on the Web Nature has also offered a potential solution: bacteriophage, viruses that naturally destroy bacteria. Dana Taylor, USA TODAY, 31 July 2023 Some scientists see promise in a treatment called bacteriophage therapy. Allison Parshall, Scientific American, 14 Apr. 2023 Angela Belchersuccessfully transformed the M13 bacteriophage, a virus harmless to humans, into the cathode and anode of a lithium-ion battery. Jeremy Jacquot, Discover Magazine, 26 Aug. 2010 News of the outbreak's growing toll comes as the CDC says researchers at the University of California at San Diego have identified a bacteriophage that might work to treat the extensively drug-resistant bacteria. Alexander Tin, CBS News, 21 Mar. 2023 The one seen in this colored transmission electron micrograph, a T4 bacteriophage, has just injected its viral DNA into an E. coli bacterium. Colin Salter, Discover Magazine, 11 Feb. 2015 The Phage Therapy Center in the Republic of Georgia is the pioneer in providing bacteriophage treatment for a smorgasbord of bacterial infections. Rebecca Kreston, Discover Magazine, 2 May 2012 Later that year, the team built another cog in the wheel of biological computing: the ability to send arbitrary messages between cells, again with help from a bacteriophage called M13. Anil Ananthaswamy, Discover Magazine, 28 Aug. 2014 But with the discovery of antibiotics, bacteriophage research became largely forgotten, at least in the West. WIRED, 27 Sep. 2022 See More

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

Word History


International Scientific Vocabulary

First Known Use

1917, in the meaning defined above

Time Traveler
The first known use of bacteriophage was in 1917

Dictionary Entries Near bacteriophage

Cite this Entry

“Bacteriophage.” Dictionary, Merriam-Webster, Accessed 30 Sep. 2023.

Kids Definition


: any of various viruses that specifically attack bacteria

Medical Definition


bac·​te·​ri·​o·​phage bak-ˈtir-ē-ə-ˌfāj How to pronounce bacteriophage (audio) -ˌfäzh How to pronounce bacteriophage (audio)
: a virus that infects bacteria : phage
Bacteriophages invade bacterial cells and burst them open before they have a chance to produce lactic acid.Diana Morgan and Terence Monmaney, Science
bacteriophagy noun
plural bacteriophagies

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