knee vs genu

knee and genu both are nouns.

Word	Noun	Adjective	Verb	Adverb
knee	Yes	No	No	No
genu	Yes	No	No	No

As nouns, knee and genu are synonyms defined as:

knee and genu: hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella

Other synonyms of knee include articulatio genus, human knee, knee joint.

knee (noun)	genu (noun)
joint between the femur and tibia in a quadruped; corresponds to the human knee	hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella
the part of a trouser leg that provides the cloth covering for the knee
hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella