Roman nose vs olfactory organ

Roman nose and olfactory organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
Roman nose	Yes	No	No	No
olfactory organ	Yes	No	No	No

As nouns, olfactory organ is a hypernym of Roman nose; that is, olfactory organ is a word with a broader meaning than Roman nose:

Roman nose: a nose with a prominent slightly aquiline bridge
olfactory organ: the organ of smell and entrance to the respiratory tract; the prominent part of the face of man or other mammals

Other hypernyms of Roman nose include nose.

Roman nose (noun)	olfactory organ (noun)
a nose with a prominent slightly aquiline bridge	the organ of smell and entrance to the respiratory tract; the prominent part of the face of man or other mammals