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plural phages also phage
: a virus that infects bacteria : bacteriophage
They cloned the antibody genes and inserted them into phage, a virus that infects bacteria cells.Teresa L. White
Bacteriophages, also known simply as phages, came to light around 90 years ago, when two European scientists independently discovered that there are viruses that kill bacteria.John Travis


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noun combining form

: virus or cell that destroys cells

Examples of phage in a Sentence

Recent Examples on the Web
Life Phage: The most abundant life form on Earth has a unique license to kill Researchers estimate there may be as many as ten million trillion trillion phages on Earth — that’s 10 with 30 zeros after it. Big Think, 24 June 2024 These are former phages that have been domesticated by bacteria so they can be used to harm the bacteria's potential competition. John Timmer, Ars Technica, 14 June 2024 Once phages are isolated, a predictive algorithm simulates interactions between millions of phages and pathogens to understand which can eat which. Cecilia.butini, Vox, 4 June 2024 Widely used to treat infection before the advent of antibiotics, phages are viruses that destroy specific bacteria. Tribune News Service, The Mercury News, 18 May 2024 See all Example Sentences for phage 

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

Word History



by shortening

Noun combining form

Greek -phagos one that eats, from -phagos -phagous

First Known Use


1920, in the meaning defined above

Time Traveler
The first known use of phage was in 1920

Dictionary Entries Near phage

Cite this Entry

“Phage.” Dictionary, Merriam-Webster, Accessed 14 Jul. 2024.

Kids Definition


ˈfāj How to pronounce phage (audio)
 also  ˈfäzh

Medical Definition


plural phages also phage
: a virus that infects bacteria : bacteriophage
To infect a host bacterium, a phage will first interact with receptors on the host cell, adsorb and then inject its genome.George P. C. Salmond and Peter C. Fineran, Nature Reviews Microbiology
Phages have various possible life cycles which, along with interaction with their physical environment, dictate their role in bacterial/archaeal biology.Martha R. J. Clokie et al., Bacteriophage

More from Merriam-Webster on phage

Last Updated: - Updated example sentences
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