Lois ran to store (4)
I believe the answer is:
'store' is the definition.
(a store of crops)
'lois ran' is the wordplay.
'ran' is an anagram indicator (letters have run around).
'lois' with letters rearranged gives 'SILO'.
'to' acts as a link.
(Other definitions for silo that I've seen before include "Tower for storing grain" , "Grain store; missile site" , "Launch site" , "Missile pit" , "Store for grain or fodder" .)