Definition of endoderm in US English:


(also entoderm)


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.

    Compare with ectoderm and mesoderm
    • ‘In this tissue, therefore, the fate of some of the cells has been changed from prospective gut endoderm to mesoderm and ectoderm.’
    • ‘At a tissue level, an adult hydra is essentially a tube composed of two tissue layers, the ectoderm and the endoderm, which extend throughout the animal.’
    • ‘These cells, usually seen as being mesodermal, apparently represent another cell line originating from endoderm.’
    • ‘Other asymmetric anatomical features - such as placement of the heart and liver - are products of different layers, the mesoderm and endoderm.’
    • ‘In addition, they act as messengers, bearing molecular orders to the mesoderm and endoderm which they contact on arrival.’


Mid 19th century: from endo- ‘within’ + Greek derma ‘skin’.