'Endothelium' definitions:

Definition of 'endothelium'

From: WordNet
noun
An epithelium of mesoblastic origin; a thin layer of flattened cells that lines the inside of some body cavities

Definition of 'Endothelium'

From: GCIDE
  • Endothelium \En`do*the"li*um\, n.; pl. Endothelia. [NL., fr. Gr. 'e`ndon within + ? nipple.] (Anat.) The thin epithelium lining the blood vessels, lymphatics, and serous cavities. See Epithelium. [1913 Webster]