pleu·ra¹ / ˈploŏrə/ • n. (pl. pleu·rae / ˈploŏrē/ ) 1. each of a pair of serous membranes lining the thorax and enveloping the lungs in humans and other mammals.2. Zool. a lateral part in an animal body or structure. Compare with pleuron.DERIVATIVES: pleu·ral adj.pleu·ra² / ˈploŏrə/ • plural form of pleuron.

pleura A thin membrane which lines the inside of the chest cavity and also covers the lungs. The two ‘pleural cavities’ are enclosed compartments, with normally only a film of fluid between the layer lining the chest (parietal pleura) and the layer covering the lungs (visceral pleura). The two layers continually tend to pull away from each other, because of the stretched elastic condition of the lungs — an important factor in the mechanics of breathing. If the chest wall is penetrated by a wound, air is readily sucked into the pleural cavity, separating the two pleural layers and collapsing the lung.

Stuart Judge

pleura (anat.) membrane lining the thorax and enveloping the lungs. XVII. — medL. — Gr. pleurā́ side, rib.
So pleurisy inflammation of the pleura. XIV. — OF. pleurise (mod pleurésie) — late L. pleuriris, for earlier pleurītis — Gr. pleurîtis pleuritic XVI. — (O)F pleurétique — L. pleurīticus — Gr. pleurītikós, pleuro- comb. form of Gr. pleurā́.

pleura (pleural membrane) The double membrane that lines the thoracic cavity and covers the exterior surface of the lungs. It is a serous membrane forming a closed sac, with a small space (the pleural cavity) between the two layers.

pleura (ploor-ă) n. the covering of the lungs (visceral p.) and of the inner surface of the chest wall (parietal p.), consisting of a closed sac of serous membrane. Fluid secreted by the membrane lubricates the opposing surfaces so that they can slide painlessly over each other during breathing.
—pleural adj.