immunization

noun

im·​mu·​ni·​za·​tion ˌi-myə-nə-ˈzā-shən 

also i-ˌmyü-nə-

plural immunizations

: the act of making someone or something immune or the state of being immune : the act or result of immunizing someone or something: such as

a

: the production of immunity in a living organism against a disease or pathogenic agent

Full immunization occurs two weeks after inoculation.

The plasmids used for immunization have been altered to carry genes specifying one or more antigenic proteins normally made by a selected pathogen …

—David B. Weiner et al.

also : treatment (as by vaccination) for the purpose of making an organism immune to a disease or pathogenic agent : the administration of an immune-producing substance

Measles is the single most infectious common disease—one person with measles who blunders into a crowded room will give it to almost everyone. If there were no immunization, measles would be universal.

—Wayne Biddle

Those benefits can include preventive care, such as annual physicals, immunizations, and well-baby visits.

—Consumer Reports

b

: the providing of protection or exemption from something harmful or unwanted (such as legal action)

immunization from liability

The Interior Department is negotiating with other private landowners to extend similar immunization from prosecution to those who agree to avoid activities that might hurt the bird's chances of survival.

—Ken Miller

Examples of immunization in a Sentence

Recent Examples on the Web

In 2019, Kenya added the HPV vaccine to its routine immunization program. — Durrie Bouscaren, NPR, 25 July 2026

Only 18 national immunization surveys were undertaken and submitted this round, down from 50 in 2024 and an average of 33 per year between 2015 and 2019. — Maryanne Murray Buechner, Forbes.com, 23 July 2026

New measles cases continue to be reported across California at a regular clip, putting unvaccinated people — including babies too young to have received their first immunization — at risk of severe illness and potentially death. — Los Angeles Times, 23 July 2026

Organizations in suburban Cook County that would like the department to host an immunization clinic should complete a request form on the website. — Francine Knowles, Chicago Tribune, 20 July 2026

Word History

First Known Use

1889, in the meaning defined above

Rhymes for immunization

• abbreviation
• abomination
• acceleration
• accentuation
• accommodation
• accreditation
• acculturation
• accumulation
• acetylation
• adjudication
• administration
• adulteration

Kids Definition

immunization

noun

im·​mu·​ni·​za·​tion

ˌim-yə-nə-ˈzā-shən

: treatment (as with a vaccine) to produce immunity to a disease

Medical Definition

immunization

noun

im·​mu·​ni·​za·​tion

variants also British immunisation

ˌim-yə-nə-ˈzā-shən 

: the production of immunity in a living organism against a disease or pathogenic agent

also : treatment (as by vaccination) for the purpose of making an organism immune to a disease or pathogenic agent : the administration of an immune-producing substance

immunization against polio