germ layer vs endoblast

germ layer and endoblast both are nouns.

Word	Noun	Adjective	Verb	Adverb
germ layer	Yes	No	No	No
endoblast	Yes	No	No	No

As nouns, endoblast is a hyponym of germ layer; that is, endoblast is a word with a more specific, narrower meaning than germ layer:

germ layer: (embryology) any of the 3 layers of cells differentiated in embryos following gastrulation
endoblast: the inner germ layer that develops into the lining of the digestive and respiratory systems

Other hyponyms of germ layer include ectoblast, ectoderm, exoderm, mesoblast, mesoderm, endoderm, entoblast, entoderm, hypoblast.

germ layer (noun)	endoblast (noun)
(embryology) any of the 3 layers of cells differentiated in embryos following gastrulation	the inner germ layer that develops into the lining of the digestive and respiratory systems