pneumonia
noun
pneu·mo·nia
nu̇-ˈmō-nyə 
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
Goldstein was comatose and had been placed on a ventilator after pneumonia overwhelmed her lungs.
—
John Blake,
CNN Money,
5 July 2026
Legionnaires is a bacterial pneumonia caused by the bacteria legionella, which grows in warm water.
—
Thomas Tracy,
New York Daily News,
4 July 2026
In the 1940s, the widespread use of penicillin allowed for the treatment of diseases that were once fatal, including pneumonia, strep infections, wound infections and sepsis.
—
Melissa Rudy,
FOXNews.com,
3 July 2026
Deaths from flu and pneumonia, meanwhile, rose to be the eighth-leading cause of death last year amid lower uptake of the flu shot.
—
Rachel Roubein,
Washington Post,
2 July 2026
See All Example Sentences for pneumonia
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John Blake,
CNN Money,
5 July 2026
Legionnaires is a bacterial pneumonia caused by the bacteria legionella, which grows in warm water.
—
Thomas Tracy,
New York Daily News,
4 July 2026
In the 1940s, the widespread use of penicillin allowed for the treatment of diseases that were once fatal, including pneumonia, strep infections, wound infections and sepsis.
—
Melissa Rudy,
FOXNews.com,
3 July 2026
Deaths from flu and pneumonia, meanwhile, rose to be the eighth-leading cause of death last year amid lower uptake of the flu shot.
—
Rachel Roubein,
Washington Post,
2 July 2026
See All Example Sentences for pneumonia
Cite this Entry
“Pneumonia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pneumonia. Accessed 6 Jul. 2026.
Copy CitationKids Definition
pneumonia
noun
pneu·mo·nia
n(y)u̇-ˈmō-nyə
: 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
: 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
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