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 contagious intestinal illness contagious skin rash contagious viruses — see also contagious disease
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

Keep scrolling for more

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.
See More
Recent Examples on the Web Believed to be about two times more contagious than earlier strains of COVID-19, the P.1 coronavirus variant originated in the Amazon in November 2020. Detroit Free Press, 1 June 2021 Studies have shown the strain to be up to 2.2 times more contagious than previous versions and possibly more deadly—a hypothesis researchers are still investigating. Luciana Magalhaes, WSJ, 27 May 2021 The virus, which the World Health Organization dubbed a variant of concern last week, appears to be more contagious than older coronavirus variants. Anna Kuchment, Dallas News, 19 May 2021 In a weekly report published Tuesday, the WHO warned that a variant first discovered in India may be more contagious than most versions of the coronavirus. Elinor Aspegren, USA TODAY, 12 May 2021 Cities across the country have been hit hard by a recent surge in Covid-19 cases and deaths, fueled in part by new variants believed to be more contagious than older ones, as well as some Brazilians' disregard for social distancing precautions. Angela Dewan, CNN, 14 Apr. 2021 The Lancet study confirmed that the variant is more contagious than the original strain, resulting in higher viral loads in infected patients but does not necessarily produce a more lethal illness. Washington Post, 13 Apr. 2021 But this time, the threat is different: The rise in new cases is being propelled by a coronavirus variant known as B.1.1.7, first seen in Britain, which is not only more contagious than last year’s virus, but also deadlier. BostonGlobe.com, 11 Apr. 2021 These variants all appear to be more contagious than Coronavirus Classic by varying degrees, thanks to those mutations. Andy Larsen, The Salt Lake Tribune, 9 Apr. 2021

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.

See More

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

Keep scrolling for more

Learn More about contagious

Time Traveler for contagious

Time Traveler

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

See more words from the same century

Statistics for contagious

Last Updated

5 Jun 2021

Cite this Entry

“Contagious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/contagious. Accessed 12 Jun. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

More Definitions for contagious

contagious

adjective

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

WORD OF THE DAY

Test Your Vocabulary

Name that Thing: Dog Breeds

How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

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!