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

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

A true coelom arises entirely within the mesoderm germ layer and is lined by an epithelial membrane.

From Textbooks • Jan. 1, 2015

Entoderm: the innermost germ layer of the embryo, from which are derived the epithelium of the alimentary canal and accessory structures: = endoderm and hypoblast.

From Explanation of Terms Used in Entomology by Smith, John. B.