In biology, any blastodermic membrane or blastoderm; any layer of cells, forming a membrane, which enters into the structure of a germ in its early stages.(noun)
The Century Dictionary (Public Domain)
Use "germ-layer" in a sentence
"Remak is the second great name in the history of the germ-layer theory."
"The honour of being the founder of the germ-layer theory is sometimes attributed to C.F. Wolff, notably by Kölliker and O. Hertwig."
"Baer did not attach any special morphological significance to the peritoneal lining of the body cavity, as is done in more modern forms of the germ-layer theory."