Mes`o*the"li*um (?), n. [NL., fr. Gr. middle + E. epithelium.] Biol.
Epithelial mesoderm; a layer of cuboidal epithelium cells, formed from a portion of the mesoderm during the differetiation of the germ layers. It constitutes the boundary of the c&oe;lum.
© Webster 1913.