contagious

adjective

con·ta·gious | \ kən-ˈtā-jəs

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

Other Words from contagious Synonyms & Antonyms What is the Difference Between contagious and infectious? More Example Sentences Learn More about contagious

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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.

Recent Examples on the Web

Her smile is contagious, the kind that only belongs to that person in high school who was everyone’s best friend. — Candice Benbow, Glamour, "Meet KiKi Layne, the If Beale Street Could Talk Actress Everyone's Talking About," 27 Dec. 2018 Researchers have found that both rooftop solar panels and electric vehicles are contagious. — David Roberts, Vox, "For the first time, a major US utility has committed to 100% clean energy," 5 Dec. 2018 For the record, cancer is not contagious, as noted by the American Cancer Association (ACA). — De Elizabeth, Teen Vogue, "Joey King Says an Airplane Passenger Thought She Had Cancer Because of Her Shaved Head," 18 Nov. 2018 Emotional empathy is more about sharing a physical feeling with someone, as though their emotions were contagious, whereas cognitive empathy is about understanding another person’s perspective. — Sean Illing, Vox, "How meditation and psychedelic drugs could reduce political partisanship," 17 Oct. 2018 This season’s toxic masculinity seems to be contagious. — De Elizabeth, Allure, "Bachelor in Paradise," 29 Aug. 2018 The flu is a contagious respiratory illness caused by influenza viruses, the Centers for Disease Control and Prevention (CDC) says. — Korin Miller, SELF, "Can You Get the Flu Twice in One Season?," 25 Oct. 2018 Stronger sick leave policies can reduce the spread of contagious illnesses. — Shari Rudavsky, Indianapolis Star, "About that study that showed how unfit we are ... Here are a few reasons why.," 22 May 2018 Debora's contagious smile will be remembered by her mother Joanne Pitz, her sister Catherine and husband Bobby Leighton, her niece and nephew Ashley and Matthew Leighton, and her caregivers Sheri (Auntie), Kristy and Steven. — Hartford Courant, courant.com, "Debora Pitz," 21 June 2018

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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Dictionary Entries near contagious

contagious bovine pleuropneumonia

contagious distribution

Statistics for contagious

Last Updated

30 Dec 2018

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Time Traveler for contagious

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

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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

See the full definition for contagious in the English Language Learners Dictionary

contagious

adjective

con·ta·gious | \ kən-ˈtā-jəs

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

Medical Definition of contagious

1 : communicable by contact tuberculosis in the contagious stage — compare infectious sense 2

2 : bearing contagion many persons…are contagious long before they are aware of the presence of their disease — Journal of the American Medical Association

3 : used for contagious diseases a contagious ward