epidemic

American  

[ep-i-dem-ik] / ˌɛp ɪˈdɛm ɪk /

adjective

1. Also epidemical (of a disease) affecting many persons at the same time, and spreading from person to person in a locality where the disease is not permanently prevalent.

2. extremely prevalent; widespread.

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noun

1. a temporary prevalence of a disease.

2. a rapid spread or increase in the occurrence of something.

   an epidemic of riots.

epidemic British  

/ ˌɛpɪˈdɛmɪk /

adjective

1. (esp of a disease) attacking or affecting many persons simultaneously in a community or area

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noun

1. a widespread occurrence of a disease

   an influenza epidemic

2. a rapid development, spread, or growth of something, esp something unpleasant

   an epidemic of strikes

epidemic Scientific  

/ ĕp′ĭ-dĕm′ĭk /

1. An outbreak of a disease or illness that spreads rapidly among individuals in an area or population at the same time.

2. See also endemic pandemic

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epidemic Cultural  

1. A contagious disease that spreads rapidly and widely among the population in an area. Immunization and quarantine are two of the methods used to control an epidemic.

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Other Word Forms

• epidemically
  adverb
• epidemicity
  noun
• interepidemic
  adjective
• preepidemic
  noun

Etymology

Origin of epidemic

First recorded in 1595–1605; obsolete epidem(y) (from Late Latin epidēmia, from Greek epidēmía “staying in one place, among the people,” equivalent to epi- epi- + dêm(os) “people of a district” + -ia -y ³ ) + -ic

Explanation

An epidemic is a disease that spreads rapidly among many people in a community at the same time. In the 1980s, the fast-spreading AIDS epidemic transformed life on our planet. Epidemic can be used figuratively to refer to something that spreads or grows rapidly: an epidemic of laziness has taken over the tenth grade. This word is from French épidémique, ultimately from Greek epidēmia "staying in one place, among the people." The related word pandemic refers to a disease that spreads throughout an entire country or throughout the world.

Example Sentences

The Zaire strain was responsible for an explosive epidemic in West Africa in 2014 that killed more than 11,300 people—the largest Ebola outbreak in history.

From The Wall Street Journal • May 22, 2026

No vaccine or clinical treatment exists for the Bundibugyo strain of the Ebolavirus responsible for the current epidemic.

From Barron's • May 21, 2026

“I was surprised to see so many people talking not just about the situation that Jeremy’s in, but an epidemic that small businesses are facing,” Newman said.

From Los Angeles Times • May 21, 2026

Between 2013 and 2016, the Western Africa Ebola epidemic impacted 10 countries, killing upwards of 11,000 people out of an estimated 30,000 infections.

From Salon • May 20, 2026

All four of these traits apply to what Americans think of as the familiar acute epidemic diseases of childhood, including measles, rubella, mumps, pertussis, and smallpox.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

Related Words

• contagion
• outbreak
• pest
• plague
• rash
• scourge
• spread
• wave