Definition of virus in English:

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Pronunciation: /ˈvʌɪrəs/


1An infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host: the hepatitis B virus [as modifier]: a virus infection
More example sentences
  • When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane.
  • Such viruses enter the host cell and then rapidly multiply inside the cell before killing it.
  • Bacteriophages fit the definition of parasite to a T. In many cases new viruses multiply inside a host until the bacterium simply rips apart.
1.1An infection or disease caused by a virus: I’ve had a virus
More example sentences
  • The most recent problem has been a virus and she comes into the tournament short on match play.
  • Been off sick with a virus for like AGES!!!
  • After some months when it became clear that my malady wasn't disappearing like a good virus, this burden fell on my husband.
1.2A harmful or corrupting influence: the virus of cruelty that is latent in all human beings
2 (also computer virus) A piece of code which is capable of copying itself and typically has a detrimental effect, such as corrupting the system or destroying data.
Example sentences
  • A computer virus or spyware application is sending us automated requests, and it appears that your computer or network has been infected.
  • Hewlett-Packard has distributed printer drivers corrupted by a computer virus.
  • A computer virus which affected the operation of Google yesterday is spreading like wildfire.


Late Middle English (denoting the venom of a snake): from Latin, literally 'slimy liquid, poison'. The earlier medical sense, superseded by the current use as a result of improved scientific understanding, was 'a substance produced in the body as the result of disease, especially one capable of infecting others'.

  • A virus was originally the venom of a snake, and was an English borrowing of a Latin word meaning ‘slimy liquid’ or ‘poison’, that is also the source of virulent (Late Middle English). Early medical practitioners used the word for a substance produced in the body as the result of disease. The modern meaning dates from the late 19th century. The computer virus dates from the early 1970s.

Words that rhyme with virus

Cyrus, Epirus, papyrus

For editors and proofreaders

Line breaks: virus

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