Find the word definition

Wiktionary
hydropneumothorax

n. (context medicine English) The presence of both fluid and air in the pleural cavity

Wikipedia
Hydropneumothorax

Hydropneumothorax is defined as the presence of both air and fluid within the pleural space surrounding the lung. An upright chest x-ray will show air fluid levels. The horizontal fluid level is usually well defined and extends across the whole length of hemi thorax.