|inflammation of one or both lungs, in which the air sacs (alveoli) become filled with liquid, which renders them useless for breathing. It is usually caused by bacterial (esp pneumococcal) or viral infection|
|[C17: New Latin from Greek from pneumōn lung]|
pneumonia pneu·mo·nia (nu-mōn'yə, nyu-)
An acute or chronic disease marked by inflammation of the lungs and caused by viruses, bacteria, or other microorganisms and sometimes by physical and chemical irritants.
|pneumonia (n-mōn'yə) Pronunciation Key
An acute or chronic disease marked by inflammation of the lungs, especially an infectious disease caused by viruses, bacteria, or other pathogens, such as mycoplasmas. Individuals with pneumonia often have abnormal chest x-rays that show areas with fluid in the infected part of the lungs.