gastrula

Từ điển WordNet v3.1 - WordNet Dictionary

noun

double-walled stage of the embryo resulting from invagination of the blastula;
the outer layer of cells is the ectoderm and the inner layer differentiates into the mesoderm and endoderm
• Hypernyms:
embryo, conceptus, fertilized egg
• Part Meronyms:
archenteron