arm bone vs long bone

arm bone and long bone both are nouns.

Word	Noun	Adjective	Verb	Adverb
arm bone	Yes	No	No	No
long bone	Yes	No	No	No

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

arm bone: a bone in the arm
long bone: in limbs of vertebrate animals: a long cylindrical bone that contains marrow

Other hypernyms of arm bone include os longum.

arm bone (noun)	long bone (noun)
a bone in the arm	in limbs of vertebrate animals: a long cylindrical bone that contains marrow