[mass noun](Zoology & Embryology)the innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures (动 ,胚)内胚层。 比较 ectoderm 和 mesoderm
派生 endodermal adjective 语源
mid 19th cent.: from endo- 'within' + Greek derma 'skin'