revival meeting vs mass meeting

revival meeting and mass meeting both are nouns.

Word	Noun	Adjective	Verb	Adverb
revival meeting	Yes	No	No	No
mass meeting	Yes	No	No	No

As nouns, mass meeting is a hypernym of revival meeting; that is, mass meeting is a word with a broader meaning than revival meeting:

revival meeting: an evangelistic meeting intended to reawaken interest in religion
mass meeting: a large gathering of people intended to arouse enthusiasm

Other hypernyms of revival meeting include rally.

revival meeting (noun)	mass meeting (noun)
an evangelistic meeting intended to reawaken interest in religion	a large gathering of people intended to arouse enthusiasm