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
Along with a high fever, cough, and runny nose, measles also carries a risk of pneumonia and encephalitis (swelling of the brain), which can cause hearing loss, cognitive disabilities and death.
—
Cara Lynn Shultz, PEOPLE, 29 Dec. 2025
The deaths of beloved celebrities devastated us this year, such as the sudden passing of Diane Keaton from pneumonia at age 79.
—Emily Kay Votruba, EverydayHealth.com, 29 Dec. 2025
Measles can lead to serious conditions such as pneumonia, brain swelling, or even death.
—Jeff Capellini, CBS News, 28 Dec. 2025
The officer was told there was a risk of fluid in Bowie’s lungs, which could lead to pneumonia — a potentially fatal illness Johanson was all too familiar with from his last dog.
—Caleb Lunetta, San Diego Union-Tribune, 25 Dec. 2025
See All Example Sentences for pneumonia
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Cara Lynn Shultz, PEOPLE, 29 Dec. 2025
The deaths of beloved celebrities devastated us this year, such as the sudden passing of Diane Keaton from pneumonia at age 79.
—Emily Kay Votruba, EverydayHealth.com, 29 Dec. 2025
Measles can lead to serious conditions such as pneumonia, brain swelling, or even death.
—Jeff Capellini, CBS News, 28 Dec. 2025
The officer was told there was a risk of fluid in Bowie’s lungs, which could lead to pneumonia — a potentially fatal illness Johanson was all too familiar with from his last dog.
—Caleb Lunetta, San Diego Union-Tribune, 25 Dec. 2025
See All Example Sentences for pneumonia
Cite this Entry
“Pneumonia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pneumonia. Accessed 31 Dec. 2025.
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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