Before midnight, routine presence (10)
I believe the answer is:
attendance
'presence' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for attendance that I've seen before include "Service" , "Gate - enact Dante (anag)" , "Number present" , "Act of being present" , "Number at gathering" .)