femoris vs leg bone

femoris and leg bone both are nouns.

Word	Noun	Adjective	Verb	Adverb
femoris	Yes	No	No	No
leg bone	Yes	No	No	No

As nouns, leg bone is a hypernym of femoris; that is, leg bone is a word with a broader meaning than femoris:

femoris: the longest and thickest bone of the human skeleton; extends from the pelvis to the knee
leg bone: a bone of the leg

femoris (noun)	leg bone (noun)
the longest and thickest bone of the human skeleton; extends from the pelvis to the knee	a bone of the leg