Setting for a cathedral clock (3)
I believe the answer is:
see
'clock' is the definition.
(clock can mean to see or realise)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for see that I've seen before include "Perceive, watch" , "Jurisdiction of a bishop" , "Appreciate" , "Envisage; ensure" , "twig" .)