nostril vs naris

nostril and naris both are nouns.

Word	Noun	Adjective	Verb	Adverb
nostril	Yes	No	No	No
naris	Yes	No	No	No

As nouns, naris is a hypernym of nostril; that is, naris is a word with a broader meaning than nostril:

nostril: either one of the two external openings to the nasal cavity in the nose
naris: any of the openings to the nasal cavities that allow air to flow through the cavities to the pharynx

nostril (noun)	naris (noun)
either one of the two external openings to the nasal cavity in the nose	any of the openings to the nasal cavities that allow air to flow through the cavities to the pharynx