Ceremonial; rite (6)
I believe the answer is:
ritual
I believe this clue is a double definition.
'ceremonial' is the first definition.
(I've seen this in another clue)
'rite' is the second definition.
(I know that rite can be written as ritual)
(Other definitions for ritual that I've seen before include "Code of ceremonies" , "Habit, routine" , "Customary observance or practice" , "Codified ceremony" , "Ceremony following a prescribed order" .)