-ˈthēlēəm noun
( plural mesothe·lia -lēə)
Etymology: New Latin, from mes- + epi thelium
: epithelium that is derived from mesoderm, that in vertebrate embryos lines the primordial body cavity, and that gives rise to the epithelium of the peritoneum, pericardium, and pleurae, the striated muscles, the heart muscle, the epithelium of the urogenital organs except the bladder and urethra, and several minor structures