Grain store is put up on empty lido (4)
I believe the answer is:
silo
'grain store' is the definition.
(I've seen this before)
'is put up on empty lido' is the wordplay.
'put up' shows that the letters should be reversed in order.
'on' says to put letters next to each other.
'empty' says to hollow out the word (remove centre letters).
'lido' with its middle taken out is 'lo'.
'is' written backwards gives 'si'.
'si'+'lo'='SILO'
(Other definitions for silo that I've seen before include "Store for grain or fodder" , "Farm grain storer" , "Farm tower" , "Underground chamber for a missile" , "Storage space for fodder" .)