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

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.
Recent Examples on the Web But the highly contagious Omicron variant has put Beijing's zero Covid policy under its greatest test, and massive lockdowns have brought economic activity to a halt in major cities. Laura He, CNN, 9 May 2022 The 100 million figure is not as high as the total number of Americans known to have become infected with the highly contagious omicron variant during a wave in December and January. Arkansas Online, 8 May 2022 The 100 million figure is not as high as the total number of Americans known to have become infected with the highly contagious Omicron variant during the wave in December and January. Sheryl Gay Stolberg, New York Times, 6 May 2022 Beijing’s rigid approach to the highly contagious Omicron variant has rattled an already shaky economy. Jacky Wong, WSJ, 6 May 2022 Case numbers generally have been lower in recent weeks, and public health experts estimate cases of the highly contagious omicron variant peaked in Arizona around mid-January. Alison Steinbach, The Arizona Republic, 4 May 2022 Beijing is starting to resemble other Chinese cities grappling with the highly contagious Omicron variant of the coronavirus. Elvia Limón, Los Angeles Times, 2 May 2022 What remains unclear is whether the highly contagious variant will breach Beijing’s defenses, and whether containment measures will be enforced in a way that minimizes disruption to daily life and the work of government and businesses. Ken Moritsugu, ajc, 29 Apr. 2022 The latest outbreak, driven by the highly contagious omicron variant, has spread nationwide, but has been particularly large in Shanghai. NBC News, 25 Apr. 2022 See More

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.

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

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

Dictionary Entries Near contagious

contagiosity

contagious

contagious abortion

See More Nearby Entries 

Statistics for contagious

Last Updated

12 May 2022

Cite this Entry

“Contagious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/contagious. Accessed 16 May. 2022.

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

More Definitions for contagious

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

More from Merriam-Webster on contagious

Nglish: Translation of contagious for Spanish Speakers

Britannica English: Translation of contagious for Arabic Speakers

WORD OF THE DAY

Test Your Vocabulary

Eponyms: Words Named After People

True or False

Test your knowledge - and maybe learn something along the way.

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!