infection
Americannoun
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infections
plural
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an infecting with germs of disease, as through the medium of infected insects, air, water, or clothing.
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an infecting agency or influence.
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an infectious disease.
Is this infection very dangerous?
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the condition of suffering an infection.
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corruption of another's opinions, beliefs, moral principles, etc.; moral contamination.
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an influence or impulse passing from one to another and affecting feeling or action.
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Grammar. (in Celtic languages) assimilation in which a vowel is influenced by a following vowel or semivowel; umlaut.
noun
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invasion of the body by pathogenic microorganisms
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the resulting condition in the tissues
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an infectious disease
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the act of infecting or state of being infected
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an agent or influence that infects
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persuasion or corruption, as by ideas, perverse influences, etc
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The invasion of the body of a human or an animal by a pathogen such as a bacterium, fungus, or virus. Infections can be localized, as in pharyngitis, or widespread as in sepsis, and are often accompanied by fever and an increased number of white blood cells. Individuals with immunodeficiency syndromes are predisposed to certain infections.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of infection
1350–1400; Middle English infeccio ( u ) n < Late Latin infectiōn- (stem of infectiō ). See infect, -ion
Explanation
Infections are what happens when germs invade your body and cause a disease. Some, like meningitis, an infection of the tissues covering the brain and spinal cord, can be deadly. Others, like the common cold, are relatively mild. If you've ever scraped your knee and ended up with a swollen, achy scab, you know that you can develop an infection if you don't tend to your cuts and wounds and keep them clean. Though the word was traditionally used in the medical sense to refer to the pathogens, or germs, that cause illness, infection is now sometimes used in a broader sense to refer to people or things that act like pathogens. If rival gangs turn a neighborhood into a battleground, you could refer to this as an infection of gang activity.
Vocabulary lists containing infection
“About Edward Jenner” from the Jenner Institute
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Life Science: Human Systems
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National Nurses Week: Medical Branches and Conditions
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Symptoms of Ebola, which are similar to the flu or malaria, include fever, headache and tiredness, and can begin suddenly within two to 21 days of infection.
From BBC ● Aug. 17, 2026
When the data center issue first flared up last year, Bare was in the hospital with a severe spinal infection, fielding worried updates from her mother.
From The Wall Street Journal ● Aug. 16, 2026
More than 2.4 million people today live with hepatitis C, a viral infection that primarily affects the liver and can ultimately destroy it.
From MarketWatch ● Aug. 13, 2026
Ebola is a rare but deadly viral disease, with symptoms appearing within two to 21 days of infection.
From BBC ● Aug. 13, 2026
Many American doctors, including Garfield's, still refused to accept that microbes caused infection.
From "Ambushed!" by Gail Jarrow
Most infections are asymptomatic, but about one in 100 involve neuroinvasive disease: meningitis, encephalitis or paralysis.
From Los Angeles Times ● Aug. 16, 2026
The bacteria is linked to sometimes fatal infections, especially in young children, the elderly and people with weakened immunity.
From Barron's ● Aug. 14, 2026
The CDC on Wednesday said public-health officials in several states were investigating an outbreak of salmonella infections tied to jalapeno peppers.
From MarketWatch ● Aug. 6, 2026
The parasitology bench—focused on infections caused by parasites—has transitioned to a full-capacity, seven-day-a-week operation.
From The Wall Street Journal ● Aug. 5, 2026
So he’ll need antibiotics to fight off any infections.
From "Booked" by Kwame Alexander
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
