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

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

The committee’s verdicts will help determine which vaccines insurance companies and the federal government pay for, decisions that will inevitably shape countless Americans’ immunization habits. —Tom Bartlett, The Atlantic, 13 June 2025

The landscape was further muddled by the CDC announcing that the Covid-19 vaccines would remain on the childhood immunization schedule, contradicting RFK Jr.’s decree. —Shreyas Teegala, Smithsonian Magazine, 12 June 2025

Kennedy, a longtime anti-vaccine activist before joining the Trump administration, announced May 27 that COVID vaccines would be removed from the CDC’s immunization schedule for healthy pregnant women and healthy children. —Kff Health News, San Diego Union-Tribune, 10 June 2025

Its membership consists of medical and public health experts who are knowledgeable about immunization and vaccines and do not work for the government or vaccine manufacturers, according to health policy nonprofit KFF. —Chantelle Lee, Time, 9 June 2025

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 creation of immunity usually against a particular disease

especially : treatment (as by vaccination) of an organism for the purpose of making it immune to a particular pathogen

immunization against polio