narthex vs vestibule

narthex and vestibule both are nouns.

Word	Noun	Adjective	Verb	Adverb
narthex	Yes	No	No	No
vestibule	Yes	No	No	No

As nouns, vestibule is a hypernym of narthex; that is, vestibule is a word with a broader meaning than narthex:

Other hypernyms of narthex include antechamber, anteroom, entrance hall, foyer, hall, lobby.

narthex (noun)	vestibule (noun)
a vestibule leading to the nave of a church	a large entrance or reception room or area
portico at the west end of an early Christian basilica or church	any of various bodily cavities leading to another cavity (as of the ear or vagina)