Middle of the month (4)
I believe the answer is:
ides
'middle of the month' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ides that I've seen before include "mid-month for the Romans" , "day in Rome" , "For Romans, a day" , "Orfes" , "Unlucky day for Julius Caesar" .)