n, pl  pleu*rae  or  pleuras  :  either of a pair of two-walled sacs of serous membrane each of which lines one lateral half of the thorax, has an inner layer closely adherent to the corresponding lung, is reflected at the root of the lung to form a parietal layer that adheres to the walls of the thorax, the pericardium, the upper surface of the diaphragm, and adjacent parts, and contains a small amount of serous fluid that minimizes the friction of respiratory movements .
 
 
 
Similar sounding terms:  pal·lor  pi·la·ry  pil·lar  po·lar 
 
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