Keep pit area back to store harvest (9)
I believe the answer is:
acropolis
'keep' is the definition.
(thesaurus)
'pit area back to store harvest' is the wordplay.
I cannot really see how this works, but
'area' could be 'a' (maths abbreviation) and 'a' is found in the answer.
'harvest' could be 'crop' ('crop' can be a synonym of 'harvest') and 'crop' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for acropolis that I've seen before include "Parthenon location" , "Upper fortified part of Greek city - Athens's is famous" , "classical site" , "Citadel of ancient Greece" , "Imposing building" .)