pneumonia

noun

pneu·​mo·​nia nu̇-ˈmō-nyə How to pronounce pneumonia (audio)
nyu̇-
: an acute disease that is marked by inflammation of lung tissue accompanied by infiltration of alveoli and often bronchioles with white blood cells (such as neutrophils) and fibrinous exudate, is characterized by fever, chills, cough, difficulty in breathing, fatigue, chest pain, and reduced lung expansion, and is typically caused by an infectious agent (such as a bacterium, virus, or fungus) see bronchopneumonia, pneumocystis carinii pneumonia, primary atypical pneumonia compare pneumonitis

Examples of pneumonia in a Sentence

He caught pneumonia over the winter.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Eberhart says Nalwamba had pneumonia for three weeks in detention, was never treated and has had a chest cough since June. — Victoria Craw, Washington Post, 22 Oct. 2026 Athanasiou said Nalwamba was diagnosed with pneumonia in January, lost more than 30 pounds and collapsed while detained. — Tori Mason, CBS News, 21 Oct. 2026 Other symptoms can include low platelet counts, pneumonia, and neurologic complications. — Beth Mole, ArsTechnica, 19 Oct. 2026 The younger Paul’s relationship with Braunstein, however, was cold — ever since Les Paul died in 2009 of severe pneumonia complications amid what Gene characterizes as communication issues between Braunstein and the family. — Brenna Ehrlich, Rolling Stone, 17 Oct. 2026 See All Example Sentences for pneumonia

Word History

Etymology

New Latin, from Greek, from pneumōn lung, alteration of pleumōn — more at pulmonary

First Known Use

1603, in the meaning defined above

Time Traveler
The first known use of pneumonia was in 1603

Phrases Containing pneumonia

Rhymes for pneumonia

See All Rhymes for pneumonia

Browse Nearby Words

pneumonectomy
pneumonia
pneumonic
See all Nearby Words

Cite this Entry

“Pneumonia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pneumonia. Accessed 28 Oct. 2026.

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Kids Definition

pneumonia

noun
pneu·​mo·​nia n(y)u̇-ˈmō-nyə How to pronounce pneumonia (audio)
: a disease of the lungs marked by inflammation, congestion, fever, cough, and difficulty in breathing and caused especially by infection

Medical Definition

pneumonia

noun
pneu·​mo·​nia n(y)u̇-ˈmō-nyə How to pronounce pneumonia (audio)
: an acute disease that is marked by inflammation of lung tissue accompanied by infiltration of alveoli and often bronchioles with white blood cells (as neutrophils) and fibrinous exudate, is characterized by fever, chills, cough, difficulty in breathing, fatigue, chest pain, and reduced lung expansion, and is typically caused by an infectious agent (as a bacterium, virus, or fungus) see bronchopneumonia, lobar pneumonia, pneumocystis carinii pneumonia, primary atypical pneumonia

More from Merriam-Webster on pneumonia

Britannica.com: Encyclopedia article about pneumonia

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