noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A stage in the development of embryos of most animals consisting of a three-layered sac of ectoderm, mesoderm and endoderm.
2. 2
   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 wordnet

Etymology

From German Gastrula, coined by Ernst Haeckel in his 1872 work "Biology of Calcareous Sponges".

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.