genu vs ginglymoid joint

genu and ginglymoid joint both are nouns.

Word	Noun	Adjective	Verb	Adverb
genu	Yes	No	No	No
ginglymoid joint	Yes	No	No	No

As nouns, ginglymoid joint is a hypernym of genu; that is, ginglymoid joint is a word with a broader meaning than genu:

genu: hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella
ginglymoid joint: a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane

Other hypernyms of genu include ginglymus, hinge joint.

genu (noun)	ginglymoid joint (noun)
hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella	a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane