Diamond division (6)
I believe the answer is:
inning
'diamond division' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for inning that I've seen before include "Part of game" , "One of nine divisions of play in baseball" , "Period of play in baseball or cricket" , "Division of play in cricket" , "Division of play in baseball" .)