epithelium of mesodermal origin; specif., the thin layer of mesodermal epithelial cells lining the pericardial, pleural, peritoneal, and scrotal cavities
Origin:
ModL < meso- + (epi)thelium
See mesothelium in American Heritage Dictionary 4
nounpl.mes·o·the·li·a(-lē-ə)
The layer of flat cells of mesodermal origin that lines the embryonic body cavity and gives rise to the squamous cells of the peritoneum, pericardium, and pleura.