pneumonia

n. inflammation of the lungs, severe congestion of the lungs

Pneumonia is an illness of the lungs and respiratory system in which the alveoli (microscopic air-filled sacs of the lung responsible for absorbing oxygen from the atmosphere) become inflamed and flooded with fluid. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs.
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Pneumonia is an infection of the lung that can be caused by nearly any class of organism known to cause human infections. [more]Pneumonia - Community and Resources

Noun
1. respiratory disease characterized by inflammation of the lung parenchyma (excluding the bronchi) with congestion caused by viruses or bacteria or irritants
(hypernym) respiratory disease, respiratory illness, respiratory disorder
(hyponym) bronchopneumonia, bronchial pneumonia

n. pneumonia, inflammation of the lungs