1) Kind of chest cavity 2) Of lung membranes 3) Of the lung lining 4) Serosa 5) Serous membrane 
• (a.) Of or pertaining to the pleura or pleurae, or to the sides of the thorax.
Concerning the side walls of the body.
(ploor´әl) pertaining to the pleura.
Pleu'ral adjective (Anat.) Of or pertaining to the pleura or pleuræ, or to the sides of the thorax. 
Type: Term Pronunciation: plūr′ăl Definitions: 1. Relating to the pleura.
Pleural: Pertaining to the pleura, the thin covering that protects the lungs. The term 'pleural' is pronounced like 'plural' (but does not have plural meanings).
(ploor;al) Pertaining to the serous membranes associated with the lungs.
[adj] - of or relating to the pleura or the walls of the thorax
adjective of or relating to the pleura or the walls of the thorax; `pleural muscles`