Rite

DEF: a religious or other solemn ceremony or act.

EX: The rite of Catholic baptism is the ceremony that initiates a child (or adult) into the Catholic faith and membership into the church.

Merriam-Webster Online Dictionary
rite (noun)
1.
a) a prescribed form or manner governing the words or actions for a ceremony
b) the ceremonial practices of a church or group of churches
2.
a ceremonial act or action - initiation rites
3.
a division of the Christian church using a distinctive liturgy