germ layer vs mesoderm

germ layer and mesoderm both are nouns.

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

As nouns, mesoderm is a hyponym of germ layer; that is, mesoderm 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
mesoderm: the middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue

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

germ layer (noun)	mesoderm (noun)
(embryology) any of the 3 layers of cells differentiated in embryos following gastrulation	the middle germ layer that develops into muscle and bone and cartilage and blood and connective tissue