acolyte vs altar boy

acolyte and altar boy both are nouns.

Word	Noun	Adjective	Verb	Adverb
acolyte	Yes	No	No	No
altar boy	Yes	No	No	No

As nouns, altar boy is a hyponym of acolyte; that is, altar boy is a word with a more specific, narrower meaning than acolyte:

acolyte: someone who assists a priest or minister in a liturgical service; a cleric ordained in the highest of the minor orders in the Roman Catholic Church but not in the Anglican Church or the Eastern Orthodox Churches
altar boy: a boy serving as an acolyte

Other hyponyms of acolyte include thurifer.

acolyte (noun)	altar boy (noun)
someone who assists a priest or minister in a liturgical service; a cleric ordained in the highest of the minor orders in the Roman Catholic Church but not in the Anglican Church or the Eastern Orthodox Churches	a boy serving as an acolyte