Communion vs ritual

Communion and ritual both are nouns.

Word	Noun	Adjective	Verb	Adverb
Communion	Yes	No	No	No
ritual	Yes	Yes	No	No

As nouns, ritual is a hypernym of Communion; that is, ritual is a word with a broader meaning than Communion:

Communion (noun)	ritual (noun)
the act of participating in the celebration of the Eucharist	any customary observance or practice
	the prescribed procedure for conducting religious ceremonies
	stereotyped behavior

Communion (adjective)	ritual (adjective)
	of or relating to or employed in social rites or rituals
	of or relating to or characteristic of religious rituals