contagious

adjective
con·​ta·​gious | \ kən-ˈtā-jəs How to pronounce contagious (audio) \

Definition of contagious

1 : transmissible by direct or indirect contact with an infected person contagious diseases
2 : bearing contagion contagious people
3 : used for contagious diseases a contagious ward
4 : exciting similar emotions or conduct in others contagious enthusiasm contagious laughter

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Other Words from contagious

contagiously adverb
contagiousness noun

What is the Difference Between contagious and infectious?

The words contagious and infectious can be confusing because they do not designate wholly distinct categories; something is not either contagious or infectious.

Essentially, infectious diseases and contagious diseases are caused by disease-producing agents such as bacteria and viruses, but they differ in that contagious diseases can be spread to other people by direct or indirect contact.

Anything contagious, such as the flu, is always automatically infectious: if you can catch it from someone, it's being passed to you via an infectious agent, which is the thing that gets you sick—usually a virus or a bacteria.

The reverse, however, isn't true. Just because something is infectious does not mean it's contagious. Food poisoning, for example, is infectious but not contagious: food can be contaminated with a bacteria (an infectious agent) that makes you sick, but you can't give your food poisoning to someone else by shaking their hand or even giving them a kiss.

Both contagious and infectious are also used figuratively, often in much happier contexts: laughter can be contagious; someone's enthusiasm can be infectious. While both words are used figuratively of both pleasant and unpleasant things, contagious is more often chosen for the unpleasant, as when it's grumpiness or fear that seems to be spreading.

Examples of contagious in a Sentence

It's a highly contagious virus. I have a cold and I'm still contagious. I'm sick, but the doctor says I'm not contagious.
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Recent Examples on the Web With more than 24,000 people infected, the impact of the highly contagious disease is also beginning to be felt by automakers in other parts of the world. NBC News, "China set to lose out on production of 1M vehicles as coronavirus closes car plants," 5 Feb. 2020 According to the medical center’s website, the program can decline bodies based on certain criteria, such as cases of a contagious disease or severe cases of obesity or jaundice. Nataly Keomoungkhoun, Dallas News, "What’s the organ donation process? Curious Texas investigates," 5 Feb. 2020 New contagious diseases are, of course, prone to induce panic. Michael Brendan Dougherty, National Review, "The Coronavirus Plague and Social Media," 31 Jan. 2020 The strict vaccination requirements proposed come in the wake of massive outbreaks of measles this year that threatened the country’s status of having eliminated the highly contagious, vaccine-preventable disease. Beth Mole, Ars Technica, "Frenzied anti-vaxxers deter NJ lawmakers from voting on religious exemptions," 17 Dec. 2019 The cussing has become so contagious that ABC warned participants in the last Democratic debate there would be no broadcast delay, hence no time to bleep four-letter words. Author: Mark Z. Barabak, Anchorage Daily News, "What the #%&@?! Trump and 2020 Democrats are cursing a blue streak," 24 Sep. 2019 The cussing has become so contagious that ABC warned participants in the last Democratic debate there would be no broadcast delay, hence no time to bleep four-letter words. Los Angeles Times, "What the #%&@?! Trump and 2020 Democrats are cursing a blue streak," 23 Sep. 2019 Because the disease is so contagious, an emergency shelter was established to handle dogs infected or showing signs of exposure. Joan Morris, The Mercury News, "East Bay shelters get help with flu-quarantined dogs," 11 July 2019 In part, this is because Crowe’s performance oscillates between leering plutocrat and raving paranoiac, without nailing the fanaticism in between that made Ailes’s vision of America so contagious. Sophie Gilbert, The Atlantic, "The Loudest Voice Stops Short of Revealing Roger Ailes," 27 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'contagious.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of contagious

14th century, in the meaning defined at sense 1

History and Etymology for contagious

Middle English, "contaminating, communicable," borrowed from Anglo-French & Late Latin; Anglo-French, borrowed from Late Latin contāgiōsus, from Latin contāgiō "contact, contagion" + -ōsus -ous

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Time Traveler for contagious

Time Traveler

The first known use of contagious was in the 14th century

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Statistics for contagious

Last Updated

11 Feb 2020

Cite this Entry

“Contagious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/contagious. Accessed 16 Feb. 2020.

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More Definitions for contagious

contagious

adjective
How to pronounce contagious (audio)

English Language Learners Definition of contagious

: able to be passed from one person or animal to another by touching
: having a sickness that can be passed to someone else by touching
: capable of being easily spread to others : causing other people to feel or act a similar way

contagious

adjective
con·​ta·​gious | \ kən-ˈtā-jəs How to pronounce contagious (audio) \

Kids Definition of contagious

1 : able to be passed from one individual to another through contact a contagious disease
2 : having a sickness that can be passed to someone else
3 : causing other people to feel or act a similar way a contagious laugh

contagious

adjective
con·​ta·​gious | \ -jəs How to pronounce contagious (audio) \

Medical Definition of contagious

1 : communicable by contact tuberculosis in the contagious stage
2 : bearing contagion many persons…are contagious long before they are aware of the presence of their diseaseJournal of the American Medical Association
3 : used for contagious diseases a contagious ward

Other Words from contagious

contagiously adverb
contagiousness noun

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