Lois ran store (4)
I believe the answer is:
silo
'store' is the definition.
(a store of crops)
'lois ran' is the wordplay.
'ran' indicates an anagram (letters have run around).
'lois' anagrammed gives 'SILO'.
(Other definitions for silo that I've seen before include "Grain storage area" , "Storage pit, tower" , "Grain container for oils" , "Grain store; missile site" , "Grain storage tower" .)