mesothelium

https://doi.org/10.1351/goldbook.10948

Single layer of flattened cells forming an epithelium that lines serous cavities such as the peritoneum, pleura, and pericardium.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 778 [Terms] [Paper]