Store turned over in coliseum (4)
I believe the answer is:
silo
'store' is the definition.
(a store of crops)
'turned over in coliseum' is the wordplay.
'turned over' says the letters should be written in reverse.
'in' says the answer is hidden in the clue.
'olis' can be found hidden inside 'coliseum'.
'olis' backwards is 'SILO'.
(Other definitions for silo that I've seen before include "Launch site" , "Grain store; missile site" , "Large container for oils" , "Storage space for fodder" , "Farm store; soil (anag.)" .)