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virus

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noun vi·rus \ˈvī-rəs\

Definition of virus

plural vi·rus·es

  1. 1 archaic :  venom 1

  2. 2 a :  the causative agent of an infectious disease b :  any of a large group of submicroscopic infective agents that are regarded either as extremely simple microorganisms or as extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, lower animals, or plants; also :  filterable virus c :  a disease or illness caused by a virus

  3. 3 :  something that poisons the mind or soul <the force of this virus of prejudice — V. S. Waters>

  4. 4 :  a computer program that is usually hidden within another seemingly innocuous program and that produces copies of itself and inserts them into other programs and usually performs a malicious action (as destroying data)



Examples of virus

  1. Is the illness caused by bacteria or a virus?

  2. I think I have the virus that's going around this winter.

  3. The software checks your hard drive for viruses.



Origin of virus

Latin, venom, poisonous emanation; akin to Greek ios poison, Sanskrit viṣa; in senses 2 & 4, from New Latin, from Latin


First Known Use: 1599

Other Microbiology Terms

Rhymes with virus


Medical Dictionary

virus

play
noun vi·rus \ˈvī-rəs\

Medical Definition of virus

  1. 1a:  the causative agent of an infectious diseaseb:  any of a large group of submicroscopic infective agents that are regarded either as extremely simple microorganisms or as extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semipermeable membrane, that are capable of growth and multiplication only in living cells, and that cause various important diseases in humans, animals, or plants; also :  filterable virusc:  a disease caused by a virus

  2. 2:  an antigenic but not infective material (as vaccine lymph) obtainable from a case of an infectious disease




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