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
The death certificate listed Fisher’s cause of death as septic shock, a bacterial infection, acute kidney failure and pneumonia.
—
Theresa Clift, Sacbee.com, 10 Feb. 2026
The disease can lead to serious complications such as pneumonia, swelling of the brain and death.
—N'dea Yancey-Bragg, USA Today, 10 Feb. 2026
Garibay said the case is emotional for her as her brother, who was at the facility, died previously at the hospital from asphyxiation pneumonia.
—Livi Stanford, Hartford Courant, 10 Feb. 2026
In addition to complications like pneumonia, dehydration, and ear infections, between one and three in 1,000 children will develop encephalitis — irritation and swelling of the brain — either during their measles infection, or several months later.
—Elizabeth Yuko, Rolling Stone, 7 Feb. 2026
See All Example Sentences for pneumonia
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Theresa Clift, Sacbee.com, 10 Feb. 2026
The disease can lead to serious complications such as pneumonia, swelling of the brain and death.
—N'dea Yancey-Bragg, USA Today, 10 Feb. 2026
Garibay said the case is emotional for her as her brother, who was at the facility, died previously at the hospital from asphyxiation pneumonia.
—Livi Stanford, Hartford Courant, 10 Feb. 2026
In addition to complications like pneumonia, dehydration, and ear infections, between one and three in 1,000 children will develop encephalitis — irritation and swelling of the brain — either during their measles infection, or several months later.
—Elizabeth Yuko, Rolling Stone, 7 Feb. 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 14 Feb. 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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