Three hours before noon (4)
I believe the answer is:
nine
'three hours before noon' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nine that I've seen before include "So many" , "Short time for a wonder" , "Number of the ancient Muses" , "Number of players in a baseball fielding team" , "Days Lady Jane 5 ac reigned" .)