Search Result for "atelectasis": 
Wordnet 3.0

NOUN (1)

1. collapse of an expanded lung (especially in infants); also failure of pulmonary alveoli to expand at birth; 



WordNet (r) 3.0 (2006):

atelectasis
    n 1: collapse of an expanded lung (especially in infants); also
         failure of pulmonary alveoli to expand at birth