internal nostril vs posterior nasal aperture

internal nostril and posterior nasal aperture both are nouns.

Word	Noun	Adjective	Verb	Adverb
internal nostril	Yes	No	No	No
posterior nasal aperture	Yes	No	No	No

As nouns, internal nostril and posterior nasal aperture are synonyms defined as:

internal nostril and posterior nasal aperture: either one of the two posterior openings at the back of the nasal cavity leading to the nasopharynx

Other synonyms of internal nostril include choana.

internal nostril (noun)	posterior nasal aperture (noun)
either one of the two posterior openings at the back of the nasal cavity leading to the nasopharynx	either one of the two posterior openings at the back of the nasal cavity leading to the nasopharynx