germ layer vs mesoblast

germ layer and mesoblast both are nouns.

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

As nouns, mesoblast is a hyponym of germ layer; that is, mesoblast 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
mesoblast: 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, mesoderm, endoblast, endoderm, entoblast, entoderm, hypoblast.

germ layer (noun)	mesoblast (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