germ layer

American  

noun

1. one of the three primary embryonic cell layers.

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germ layer British  

noun

1. embryol any of the three layers of cells formed during gastrulation See ectoderm mesoderm endoderm

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germ layer Scientific  

1. Any of three cellular layers, the ectoderm, endoderm, or mesoderm, into which most animal embryos differentiate in the gastrula stage and from which the organs and tissues of the body develop through further differentiation.

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Etymology

Origin of germ layer

First recorded in 1875–80

Example Sentences

It was assumed that cells could be converted only to other cell types from the same germ layer, owing to their closely related developmental origins.

From Nature • Feb. 23, 2020

For instance, the work called into question whether sharing a germ layer would always ease direct reprogramming between cell types.

From Nature • Feb. 23, 2020

In protostomy, solid groups of cells split from the endoderm or inner germ layer to form a central mesodermal layer of cells.

From Textbooks • Jan. 1, 2015

Animals belonging to superphylum Lophotrochozoa are protostomes, in which the blastopore, or the point of involution of the ectoderm or outer germ layer, becomes the mouth opening to the alimentary canal.

From Textbooks • Jan. 1, 2015

E, M, H outer, middle, and inner germ layer of the embryonic shield, which is figured in median longitudinal section, seen from the left. am amnion.

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