[ vak-seen or, especially British, vak-seen, -sin ]
See synonyms for vaccine on
  1. any preventive preparation used to stimulate the body’s immune response against a specific disease, using either messenger RNA or killed or weakened bacteria or viruses to prepare the body to recognize a disease and produce antibodies.

  2. (no longer in technical use) the virus of cowpox, used in vaccination, obtained from pox vesicles of a cow or person.

  1. a software program that helps to protect against computer viruses, as by detecting them and warning the user.

  1. of or relating to vaccination.

  2. of or relating to vaccinia.

  1. of, relating to, or derived from cows.

Origin of vaccine

<New Latin (variolae) vaccīnae cowpox (in title of E. Jenner's treatise of 1798), equivalent to vacc(a) cow + -īnae, feminine plural of -īnus-ine1

Other words from vaccine

  • pro·vac·cine, adjective

Words Nearby vaccine Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use vaccine in a sentence

British Dictionary definitions for vaccine


/ (ˈvæksiːn) /

  1. a suspension of dead, attenuated, or otherwise modified microorganisms (viruses, bacteria, or rickettsiae) for inoculation to produce immunity to a disease by stimulating the production of antibodies

  2. (originally) a preparation of the virus of cowpox taken from infected cows and inoculated in humans to produce immunity to smallpox

  1. (modifier) of or relating to vaccination or vaccinia

  2. computing a piece of software designed to detect and remove computer viruses from a system

Origin of vaccine

C18: from New Latin variolae vaccīnae cowpox, title of medical treatise (1798) by Edward Jenner, from Latin vacca a cow

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for vaccine


[ văk-sēn ]

  1. A preparation of a weakened or killed pathogen, such as a bacterium or virus, or of a portion of the pathogen's structure, that stimulates immune cells to recognize and attack it, especially through antibody production. Most vaccines are given orally or by intramuscular or subcutaneous injection. See Note at Jenner.

a closer look

In the 1950s, polio epidemics left thousands of children with permanent physical disabilities. Today, infants are given a vaccine to prevent infection with the polio virus. That vaccine, like most others, works by stimulating the body's immune system to produce antibodies that destroy pathogens. Scientists usually prepare vaccines by taking a sample of the pathogen and destroying or weakening it with heat or chemicals. The inactivated or attenuated pathogen loses its ability to cause serious illness but is still able to stimulate antibody production, thereby conferring immunity. The Salk polio vaccine contains “killed” virus, while the Sabin polio vaccine contains weakened “live” poliovirus. (Many scientists no longer consider viruses to be living organisms) Scientists are also able to change the structure of viruses and bacteria at the molecular level, altering DNA so that the potential of the vaccine to cause disease is decreased. New vaccines containing harmless bits of DNA have also been developed.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for vaccine


[ (vak-seen) ]

A substance prepared from dead or living microorganisms that is introduced into the body through inoculation. The vaccine causes the development of antibodies, which produce immunity to the disease caused by the microorganism.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.