composed primarily of bodily fluid material pleural effusion material https://en.wikipedia.org/wiki/Pleural_effusion A bodily fluid material which is composed primarily of a pleural effusion, a bodily fluid that is produced in excess and accumulates in the pleural cavity, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during inhalation. pleural effusion anatomical entity