vac·​cine | \vak-ˈsēn, ˈvak-ˌsēn\

Definition of vaccine 

: a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease

Keep scrolling for more

Other Words from vaccine

vaccine adjective

Examples of vaccine in a Sentence

Recent Examples on the Web

Placement of the vaccine can also impact which shots hurt most. Erica Sweeney, Teen Vogue, "Why Do Some Vaccines Hurt More Than Others?," 24 Oct. 2018 In the meantime, the foundation is now the biggest funder of new vaccines to improve animal health. Ezra Klein, Vox, "Why Bill Gates is worried," 15 Oct. 2018 Hepatitis A infection can be prevented through vaccination and one dose of vaccine can provide substantial protection. Alexandria Hein, Fox News, "Hepatitis A outbreak in Massachusetts kills 1, sickens 64 others," 25 Sep. 2018 Just last month, parents took to the streets after hundreds of thousands of faulty vaccines were found to have been given to children across the country. Jacky Wong, WSJ, "China’s Drugs Problem Spells Opportunity for Pharma Giants," 10 Aug. 2018 The researchers are not sure why the effects of the vaccine appear to take a couple years to kick in. Alexandra Sifferlin, Time, "There’s Hope for a Vaccine to Prevent Type 1 Diabetes," 21 June 2018 But Zostavax was only about two-thirds effective in preventing shingles, and the protection was essentially gone just seven years after getting the vaccine. Julie Mazziotta,, "What to Know About the New Shingles Vaccine — and Why You Should Get It ASAP if You're Over 50," 5 July 2018 People at risk of infection for the most part are individuals who have not been vaccinated — including babies too young to get the vaccine — or haven’t had the measles. Measles is easily spread through the air when someone coughs or sneezes. Rita Giordano,, "Second suspected measles case detected in South Jersey," 5 July 2018 This team in the lab of Dr. Denise Faustman has been following 282 people, including 52 diabetics who got the vaccine. NBC News, "Can a cheap and widely available TB vaccine help diabetics?," 21 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'vaccine.' 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 vaccine

1882, in the meaning defined above

History and Etymology for vaccine

earlier, "fluid from cowpox pustules used in inoculation," noun use of vaccine "of cowpox" (in the phrases vaccine disease, vaccine matter), borrowed from New Latin vaccina (in variolae vaccinae "cowpox"), going back to Latin, feminine of vaccīnus "of or from a cow," from vacca "cow" (perhaps akin to Sanskrit vaśā "cow") + -īnus -ine entry 1; in extended sense, "preparation of organisms administered to produce immunity," in part borrowed from French vaccin, masculine derivative of vaccine "cowpox, matter from cowpox pustules," borrowed from New Latin or English

Keep scrolling for more

Learn More about vaccine

Statistics for vaccine

Last Updated

13 Nov 2018

Look-up Popularity

Time Traveler for vaccine

The first known use of vaccine was in 1882

See more words from the same year

Keep scrolling for more

More Definitions for vaccine



English Language Learners Definition of vaccine

medical : a substance that is usually injected into a person or animal to protect against a particular disease


vac·​cine | \vak-ˈsēn, ˈvak-ˌsēn\

Kids Definition of vaccine

: a preparation containing usually killed or weakened microorganisms (as bacteria or viruses) that is given usually by injection to increase protection against a particular disease


vac·​cine | \vak-ˈsēn, ˈvak-ˌ \

Medical Definition of vaccine 

1 : matter or a preparation containing the virus of cowpox used to vaccinate a person against smallpox

2 : a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease chicken pox vaccine also : a mixture of several such vaccines measles-mumps-rubella vaccine

Keep scrolling for more

Comments on vaccine

What made you want to look up vaccine? Please tell us where you read or heard it (including the quote, if possible).


a private place of worship

Get Word of the Day daily email!

Test Your Vocabulary

Difficult Vocab Quiz

  • the-education-of-achilles-eugne-delacroix
  • Which is a synonym of discomfit?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!