pneu ‧ mo ‧ ni ‧ a /njuːˈməʊniə $ nʊˈmoʊ-/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Modern Latin ; Origin: Greek , from pneumon 'lung' ]
a serious illness that affects your lungs and makes it difficult for you to breathe:
She was taken to hospital, suffering from pneumonia.