prayer meeting vs prayer service

prayer meeting and prayer service both are nouns.

Word	Noun	Adjective	Verb	Adverb
prayer meeting	Yes	No	No	No
prayer service	Yes	No	No	No

As nouns, prayer meeting and prayer service are synonyms defined as:

prayer meeting and prayer service: a service at which people sing hymns and pray together

prayer meeting (noun)	prayer service (noun)
a service at which people sing hymns and pray together	a service at which people sing hymns and pray together