[noun] [U] - a serious illness in which one or both lungs become red and swollen and filled with liquidPeople who are bedridden can easily get pneumonia.Double pneumonia is a case of the illness involving both your lungs.(figurative) You'll get/catch (double) pneumonia (= will become ill) if you go out in this cold weather without a coat!
PNEUMONIA
Meaning of PNEUMONIA in English
Cambridge English vocab. Кембриджский английский словарь. 2012