endotheliumyoudaoicibaDictYouDict[endothelium 词源字典]
"The tissue which forms a single layer of cells lining various organs and cavities of the body, especially the blood vessels, heart, and lymphatic vessels. It is formed from the embryonic mesoderm", Late 19th century: modern Latin, from endo- 'within' + Greek thēlē 'nipple'.[endothelium etymology, endothelium origin, 英语词源]