infection

American  

[in-fek-shuhn] / ɪnˈfɛk ʃən /

noun

1. an act or fact of infecting; state of being infected.

2. an infecting with germs of disease, as through the medium of infected insects, air, water, or clothing.

3. an infecting agency or influence.

4. an infectious disease.

   Is this infection very dangerous?

5. the condition of suffering an infection.

6. corruption of another's opinions, beliefs, moral principles, etc.; moral contamination.

7. an influence or impulse passing from one to another and affecting feeling or action.

8. Grammar. (in Celtic languages) assimilation in which a vowel is influenced by a following vowel or semivowel; umlaut.

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infection British  

/ ɪnˈfɛkʃən /

noun

1. invasion of the body by pathogenic microorganisms

2. the resulting condition in the tissues

3. an infectious disease

4. the act of infecting or state of being infected

5. an agent or influence that infects

6. persuasion or corruption, as by ideas, perverse influences, etc

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infection Scientific  

/ ĭn-fĕk′shən /

1. 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.

2. See also infectious disease opportunistic infection

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infection Cultural  

1. Invasion of the body or a body part by a pathogenic organism, which multiplies and produces harmful effects on the body's tissues.

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Other Word Forms

• noninfection
  noun
• postinfection
  adjective
• preinfection
  noun
• reinfection
  noun
• subinfection
  noun

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.

Example Sentences

Infection control teams sounded the alarm at the Baird Family Hospital and The Anchor Centre cancer unit after construction materials were allowed to get wet, BBC Scotland News has learned.

From BBC • Mar. 19, 2026

California’s high TB rates could be caused by a large portion of the population traveling to areas where TB is endemic, said Dr. Shruti Gohil, associate medical director for UCI Health Epidemiology and Infection Prevention.

From Los Angeles Times • Feb. 3, 2026

Infection can occur when contaminated water enters the nose during activities like swimming.

From Science Daily • Jan. 25, 2026

Infection, severe bruising, asymmetry, dryness, prolonged swelling or difficulty closing eyes completely are all possible, says Tsai—and not everyone is a good candidate, despite what your feed might suggest.

From The Wall Street Journal • Jan. 1, 2026

Infection and colitis ulcers had so compromised his system that they were amazed he had been able to play tennis just a few months earlier.

From "Big Science" by Michael Hiltzik

Related Words

• bug
• disease
• epidemic
• flu
• pollution
• virus