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

There is also a religious exemption that allows those with religious beliefs that prevent them from getting immunizations to skip them, The News & Observer previously reported. —Evan Moore, Charlotte Observer, 7 Oct. 2025

But the change raised concerns that insurers would no longer be required to cover the full cost of the immunization. —Tami Luhby, CNN Money, 7 Oct. 2025

The immunization schedules will be updated on the CDC website by Tuesday, the agency said. —Reuters, USA Today, 7 Oct. 2025

The Centers for Disease Control and Prevention (CDC) updated its immunization schedule on Monday, dropping the universal COVID-19 vaccine recommendation and also recommending that toddlers receive the chickenpox shot separately from the measles, mumps and rubella (MMR) shot. —Mary Kekatos, ABC News, 6 Oct. 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