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[vahy-ruh l] /ˈvaɪ rəl/
of, relating to, or caused by a virus.
pertaining to or involving the spreading of information and opinions about a product or service from person to person, especially on the Internet or in emails:
a clever viral ad.
See also viral marketing.
becoming very popular by circulating quickly from person to person, especially through the Internet: the most memorable viral videos;
This book is already viral two weeks before its official publication date.
pertaining to a computer virus.
go viral, to spread rapidly via the Internet, email, or other media:
Footage of the candidate's off-color remarks went viral within minutes.
Origin of viral
First recorded in 1935-40; vir(us) + -al1
Related forms
antiviral, adjective
Can be confused
viral, virile. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for viral
Contemporary Examples
Historical Examples
  • Secondary invaders and pus-forming bacteria follow the viral destruction of the lung tissue and form abscesses.

    Pandemic Jesse Franklin Bone
British Dictionary definitions for viral


of, relating to, or caused by a virus
(of a video, image, story, etc) spread quickly and widely among internet users via social networking sites, e-mail, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for viral

"of the nature of, or caused by, a virus," 1948, see virus.

Online Etymology Dictionary, © 2010 Douglas Harper
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viral in Medicine

viral vi·ral (vī'rəl)
Of, relating to, or caused by a virus.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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viral in Science
Plural viruses
  1. Any of various extremely small, often disease-causing agents consisting of a particle (the virion), containing a segment of RNA or DNA within a protein coat known as a capsid. Viruses are not technically considered living organisms because they are devoid of biological processes (such as metabolism and respiration) and cannot reproduce on their own but require a living cell (of a plant, animal, or bacterium) to make more viruses. Viruses reproduce first either by injecting their genetic material into the host cell or by fully entering the cell and shedding their protein coat. The genetic material may then be incorporated into the cell's own genome or remain in the cytoplasm. Eventually the viral genes instruct the cell to produce new viruses, which often cause the cell to die upon their exit. Rather than being primordial forms of life, viruses probably evolved from rogue pieces of cellular nucleic acids. The common cold, influenza, chickenpox, smallpox, measles, mumps, yellow fever, hemorrhagic fevers, and some cancers are among the diseases caused by viruses.

  2. Computer Science A computer program that duplicates itself in a manner that is harmful to normal computer use. Most viruses work by attaching themselves to another program. The amount of damage varies; viruses may erase all data or do nothing but reproduce themselves.

viral adjective
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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