What’s the plural of “virus”?
The plural of virus is viruses. Virus does not use a Latin plural noun form (like cactus, cacti; or fungus and fungi.)
The common cold is caused by a type of virus.
There are many different viruses that can infect humans.
Scientists identified several harmful viri in the sample.
The research focused on the properties of the viri responsible for the outbreak.
What’s the singular of virus?
Virus is singular. Viruses is plural.
What’s the definition of virus?
The Cambridge online dictionary defines the word virus as:
|
The chickenpox/flu/herpes/mumps virus; |
Irregular plural nouns (us-/-ses/-i suffixes)
Virus would belong to the category of irregular plural nouns that use Latin suffixes, including words like cactus, fungus, octopus, syllabus, stimulus, and so forth.
However, virus has adopted a regular plural noun form and uses the standard -s/-es regular plural noun ending as a plural, and uses viruses.
| singular | plural |
| virus | viruses |
| octopus | octopi (or octopuses) |
| radius | radi (or radiuses) |
| fungus | fungi (or funguses) |
| alumnus | alumni (or almunuses) |
| syllabus | syllabi (or syllabuses) |
Examples of “virus” (singular) in sentences
| Word Form | Examples |
|---|---|
| Other | It’s possible to pass on the virus to others through physical contact.
A local doctor was the first to raise the alarm about this latest virus. Several employees were off work with a vomiting virus. I don’t know exactly what’s wrong with her – I think she has some kind of virus. |
That the plural of “virus” is “viruses,” associate it with other words that form their plural by adding “-es,” like “bus” becomes “buses.”.
Examples of “viruses” (plural) in sentences
| Word Form | Examples |
|---|---|
| Other | A second question concerns whether both viruses can simultaneously infect a single neuron. From the Cambridge English Corpus
Another type of vector is based on oncolytic viruses. From the Cambridge English Corpus However, prolonged treatments may result in the inactivation of viruses. From the Cambridge English Corpus The viruses are transmitted by the faecal-oral route from person to person, and also by contaminated food and water. From the Cambridge English Corpus Their cells are far more complex than those of viruses, but they are still relatively simple. From the Cambridge English Corpus |
Synonyms for virus
- germ
- ailment
- disease
- illness
- pathogen
- bacillus
- sickness
- infection
Origin of the word virus
From etymology online on virus (n.):
|
“Poisonous substance” (a sense now archaic), from Latin virus “poison, sap of plants, slimy liquid, a potent juice,” from Proto-Italic *weis-o-(s-) “poison”. |
Read more about nouns
| Types of nouns | What’s the plural of …? |
|---|---|
| plural-only nouns | …moose? |
| mass nouns | …octopus? |
| collective nouns | …cactus? |
| abstract nouns vs. concrete nouns | …analysis? |
| possessive nouns | …curriculum? |
| regular and irregular nouns | …crisis? |
Sources
Worksheet
According to the blog post, what is the correct plural of “virus”?
The blog post states that “virus” does NOT use a Latin plural form. Which of these words mentioned in the post *can* use a Latin plural form?
Which sentence uses the correct plural form of “virus” as discussed in the post?
The blog post suggests associating the plural of “virus” with the plural of which other word to help remember it?
According to the post, what is the singular form of “viruses”?
The common cold is caused by a type of .
There are many different that can infect humans.
Prolonged treatments may result in the inactivation of .
All the tomato plants are infected with a .
The blog post indicates that using the term as the plural of virus is incorrect.
FAQs
What’s the plural of virus?
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Is “viri” the correct plural?
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Why isn’t it “viri” like fungi?
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When do I use singular virus?
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When do I use plural viruses?
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Yash, D. "What’s the Plural of Virus?." Grammarflex, Jun 25, 2025, https://www.grammarflex.com/whats-the-plural-of-virus/.
