virus

/ˈvaɪrəs/

/ˈvaɪərəs/

Other forms: viruses

Whether in the human body or on a computer, a virus is a disease-causing agent. If you come down with a nasty stomach virus, be sure to drink lots of water, get lots of rest, and stay near the toilet.

Virus comes from a Latin word that was spelled the same way. It specifically referred to the poisonous sap of certain plants, which explains why it sounds similar to viscous, a word meaning "sticky." Nowadays, it’s used to describe something that causes infectious diseases, specifically a tiny, self-replicating agent made up of genetic material and protein.

Definitions of virus

1. noun

   (virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein
   types:

   arborvirus, arbovirus

   a large heterogeneous group of RNA viruses divisible into groups on the basis of the virions; they have been recovered from arthropods, bats, and rodents; most are borne by arthropods; they are linked by the epidemiologic concept of transmission between vertebrate hosts by arthropod vectors (mosquitoes, ticks, sandflies, midges, etc.) that feed on blood; they can cause mild fevers, hepatitis, hemorrhagic fever, and encephalitis

   bacteriophage, phage

   a virus that is parasitic (reproduces itself) in bacteria

   plant virus

   a plant pathogen that is a virus consisting of a single strand of RNA

   animal virus

   an animal pathogen that is a virus

   slow virus

   a virus that remains dormant in the body for a long time before symptoms appear

   tumor virus

   a cell-free filtrate held to be a virus responsible for a specific neoplasm

   vector

   (genetics) a virus or other agent that is used to deliver DNA to a cell

   adenovirus

   any of a group of viruses including those that in humans cause upper respiratory infections or infectious pinkeye

   arenavirus

   animal viruses belonging to the family Arenaviridae

   Bunyaviridae

   a large family of arboviruses that affect a wide range of hosts (mainly vertebrates and arthropods)

   bunyavirus

   an animal virus belonging to the family Bunyaviridae; can be used as a bioweapon

   filovirus

   animal viruses belonging to the family Filoviridae

   Togaviridae

   a family of arboviruses carried by arthropods

   alphavirus

   an arbovirus of the family Togaviridae that can cause a variety of encephalitis in horses

   Flaviviridae

   a family of arboviruses carried by arthropods

   flavivirus

   animal viruses belonging to the family Flaviviridae

   Arenaviridae

   a family of arborviruses carried by arthropods

   Rhabdoviridae

   a family of arborviruses carried by arthropods

   vesiculovirus

   an animal virus that causes vesicular stomatitis

   Reoviridae

   a family of arboviruses carried by arthropods

   poxvirus

   any of a group of viruses that can cause pox diseases in vertebrates

   TMV, tobacco mosaic virus

   the widely studied plant virus that causes tobacco mosaic; it was the first virus discovered (1892)

   viroid, virusoid

   the smallest of viruses; a plant virus with its RNA arranged in a circular chromosome without a protein coat

   coliphage

   a bacteriophage that infects the bacterium Escherichia coli

   typhoid bacteriophage

   a bacteriophage specific for the bacterium Salmonella typhi

   hepadnavirus

   a group of animal DNA viruses including viruses of ducks and woodchucks and squirrels and others as well as the virus causing hepatitis B in humans

   retrovirus

   any of a group of viruses that contain two single-strand linear RNA molecules per virion and reverse transcriptase (RNA to DNA); the virus transcribes its RNA into a cDNA provirus that is then incorporated into the host cell

   myxovirus

   any of a group of RNA viruses including those that cause influenza and mumps

   picornavirus

   a group of single-strand RNA viruses with a protein coat

   herpes, herpes virus

   any of the animal viruses that cause painful blisters on the skin

   papovavirus

   any of a group of animal viruses associated with or causing papillomas or polyomas

   rhabdovirus

   any of a group of arboviruses including those causing rabies

   lyssavirus

   a neurotropic non-arbovirus of the family Rhabdoviridae that causes rabies

   reovirus

   any of a group of non-arboviruses including the rotavirus causing infant enteritis

   parvo, parvovirus

   any of a group of viruses containing DNA in an icosahedral protein shell and causing disease in dogs and cattle; not known to be associated with any human disease

   onion yellow-dwarf virus

   the virus that produces stunting and yellowing of the leaves of onion plants

   potato yellow-dwarf virus

   the virus that produces stunting and yellowing of the leaves of potato plants

   WTV, wound tumor virus

   a tumor virus transmitted by leafhoppers

   cosmid

   (genetics) a large vector that is made from a bacteriophage and used to clone genes or gene fragments

   type of:

   micro-organism, microorganism

   any living thing that is too small to be seen with the naked eye

   infectious agent, infective agent

   an agent capable of producing infection
2. noun

   a harmful or corrupting agency
   “bigotry is a virus that must not be allowed to spread”

   “the virus of jealousy is latent in everyone”

   type of:

   agency, delegacy, representation

   the state of serving as an official and authorized delegate or agent
3. noun

   a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer
   “a true virus cannot spread to another computer without human assistance”

   synonyms: computer virus

   type of:

   malevolent program, malware

   a computer program designed to have undesirable or harmful effects