virus

play
noun vi·rus \ˈvī-rəs\

Definition of virus

plural

viruses

  1. 1a :  any of a large group of submicroscopic infective agents that are usually regarded as nonliving 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, and plants; also :  filterable virusb :  a disease or illness caused by a virusc :  the causative agent of an infectious disease

  2. 2 :  something that poisons the mind or soul the force of this virus of prejudice — V. S. Waters

  3. 3 :  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 (such as destroying data)

  4. 4 archaic :  venom 1

Examples of virus in a Sentence

  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 and Etymology of virus

Latin, venom, poisonous emanation; akin to Greek ios poison, Sanskrit viṣa; in senses 1 & 3, from New Latin, from Latin


First Known Use: 1599

Other Microbiology Terms


VIRUS Defined for Kids

virus

play
noun vi·rus \ˈvī-rəs\

Definition of virus for Students

  1. 1 :  a disease-causing agent that is too tiny to be seen by the ordinary microscope, that may be a living organism or may be a very special kind of protein molecule, and that can only multiply when inside the cell of an organism

  2. 2 :  a disease caused by a virus

  3. 3 :  a usually hidden computer program that causes harm by making copies of itself and inserting them into other programs


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 usually regarded as nonliving, extremely complex molecules or sometimes as very simple microorganisms, 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, and 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



Seen and Heard

What made you want to look up virus? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

to link together in a series or chain

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

  • winning-words-from-the-national-spelling-bee-logo
  • Which is the correct spelling of the winning word from 1988?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!