embryonic disk

American  

[em-bree-on-ik disk] / ˈɛm briˌɒn ɪk ˈdɪsk /

noun

Embryology.

1. Also called embryonic shield.  in the early embryo of mammals, the flattened inner cell mass that arises at the end of the blastocyst stage and from which the embryo begins to differentiate.

2. the blastodisk of yolky eggs.

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Etymology

Origin of embryonic disk

First recorded in 1935–40

Example Sentences

Roughly two weeks after fertilization, more than half of the embryos had an embryonic disk — a flat mass of cells.

From Scientific American • May 15, 2023

He first solved the difficult problem of the transformation of this four-fold, flat, leaf-shaped, embryonic disk into the complete vertebrate body, through the conversion of the layers or plates into tubes.

From The Evolution of Man — Volume 1 by Haeckel, Ernst Heinrich Philipp August

At the beginning of germination the flat embryonic disk curves outwards, and separates on the inner side from the underlying large yelk-ball.

From The Evolution of Man — Volume 1 by Haeckel, Ernst Heinrich Philipp August

Three diagrammatic transverse sections of the embryonic disk of the higher vertebrate, to show the origin of the tubular organs from the bending germinal layers.

From The Evolution of Man — Volume 1 by Haeckel, Ernst Heinrich Philipp August

Transverse section of the embryonic disk of a chick at the end of the first day of incubation, magnified about twenty times.

From The Evolution of Man — Volume 1 by Haeckel, Ernst Heinrich Philipp August