Pile of the apples (4)
I believe the answer is:
heap
'pile' is the definition.
(I know that pile can be written as heap)
'of the apples' is the wordplay.
'of' says the answer is hidden in the clue.
'HEAP' can be found hidden inside 'the apples'.
(Other definitions for heap that I've seen before include "Mound; old car" , "good deal" , "Pile, stack" , "Amass" , "Mound, stack" .)