What does phage mean?
A phage is a virus that infects bacteria rather than human or plant cells. Its name comes from a Greek root associated with eating, reflecting the way a phage consumes the resources of its bacterial host and produces new viral particles. Phages occur naturally in soil, freshwater, and seawater, often in enormous numbers, and different phages are specialized to infect particular kinds of bacteria. This specificity has made them useful in phage therapy, in which suitable phages are selected to treat bacterial infections. They are also important tools in microbiology and biotechnology, helping researchers investigate bacterial genetics and develop methods for controlling harmful bacteria. Although the shortened form phage is widely understood in relevant scientific contexts, bacteriophage is the more explicit name for a virus that attacks bacteria.
nounA virus that infects bacteria and replicates within them. Phages are extremely abundant in the environment and are also known as bacteriophages.
- A virus that infects bacteria, using the bacterial host to reproduce.
"The researchers used a phage to target bacteria growing on the culture plate."
"A carefully selected phage was introduced into the patient's bloodstream."
"The laboratory studied how phages recognize specific strains of bacteria."
The regular plural is phages; bacteriophages is the corresponding plural of the longer form.
"Several phages were isolated from the river sample."
These virus-eats-bacteria organisms are so abundant that scientists estimate there may be more phages than bacteria in the oceans.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phage come from?
The word phage comes from the combining form of Greek phagein, meaning to eat, and was coined in the early 20th century in the context of the discovery of viruses that infect bacteria. The longer term bacteriophage combines this element with bacterium, making its host range explicit. The same Greek root appears in terms such as phagocyte and phagocytosis, which describe cells or processes involved in ingesting material.
Related word forms
How phage is actually used
The term is chiefly used in biology, medicine, and microbiology. In general usage, the more explicit term bacteriophage may be preferred when the type of virus is being introduced.
Easily confused with phage
A phage is the usual shortened name for a bacteriophage, which specifically means any virus that infects bacteria.