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.
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
Wayne Biddle Those benefits can include preventive care, such as annual physicals, immunizations, and well-baby visits. —Consumer Reports
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
Ken MillerExamples of immunization in a Sentence
Recent Examples on the Web
Some plans come with unexpected restrictions, potentially affecting coverage for care ranging from contraception to immunizations and cancer screenings.
—Emmarie Huetteman, Miami Herald, 30 Dec. 2025
Due to the increase in measles cases nationally, DPH urges anyone who has not been vaccinated or does not know their measles immunization status to contact their healthcare provider to get vaccinated with at least one dose of the MMR vaccine.
—Rick Sobey, Boston Herald, 24 Dec. 2025
While many Gen Xers and older Millennials have visceral memories (and maybe a few scars) from their days of itchy misery from chickenpox, a vaccine against varicella was added to the routine childhood immunization schedule in 1996.
—Lisa Jarvis, Twin Cities, 20 Dec. 2025
Denmark doesn’t currently recommend immunization against respiratory syncytial virus, or RSV, for children; the US does.
—Adam Cancryn, CNN Money, 19 Dec. 2025
See All Example Sentences for immunization
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Emmarie Huetteman, Miami Herald, 30 Dec. 2025
Due to the increase in measles cases nationally, DPH urges anyone who has not been vaccinated or does not know their measles immunization status to contact their healthcare provider to get vaccinated with at least one dose of the MMR vaccine.
—Rick Sobey, Boston Herald, 24 Dec. 2025
While many Gen Xers and older Millennials have visceral memories (and maybe a few scars) from their days of itchy misery from chickenpox, a vaccine against varicella was added to the routine childhood immunization schedule in 1996.
—Lisa Jarvis, Twin Cities, 20 Dec. 2025
Denmark doesn’t currently recommend immunization against respiratory syncytial virus, or RSV, for children; the US does.
—Adam Cancryn, CNN Money, 19 Dec. 2025
See All Example Sentences for immunization
Cite this Entry
“Immunization.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/immunization. Accessed 1 Jan. 2026.
Copy CitationMedical Definition
immunization
noun
im·mu·ni·za·tion
variants
also British immunisation
: 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
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