A carry-over of marriage ritual (9)
I believe the answer is:
threshold
'marriage ritual' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'a carry-over' is the wordplay.
I cannot quite understand how this works, but
'carry' could be 'hold' (synonyms) and 'hold' is located in the answer.
'over' could be 're' and 're' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for threshold that I've seen before include "Sill of house door" , "Starting point for a new experience" , "gate" , "Entrance to house - bride is carried across it" , "Point of entry" .)