A<unk>  is a condition that results from fluid accumulating in the pleural cavity. In hemothorax this fluid is blood (as in major chest injuries), in pyothorax the fluid is pus (resulting from chest infections), in chylothorax it is lymph fluid (resulting from rupture of the thoracic duct).
Hydrothorax
Pleurisy
Round pneumonia
Trapped lung
Urinothorax
Chylothorax
Hemothorax
Tracheitis