A principal embryonic cellular layer established through gastrulation; the classical three-layer organisation comprises ectoderm, mesoderm and endoderm.
A developmental designation for mesodermal and endodermal progenitors or a shared regulatory state. A shared marker profile does not prove every individual cell is bipotent.
An anterior axial mesendodermal population with morphogenetic and signalling roles. In zebrafish its coherent migration depends on contact-mediated directional information.