Store warehouse spans small island (7)
I believe the answer is:
deposit
'store' is the definition.
(I've seen this before)
'warehouse spans small island' is the wordplay.
I cannot really understand how this works, but
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is found in the answer.
'island' could be 'i' and 'i' is located in the answer.
'warehouse' could be 'depot' (I've seen this before) and 'depot' is located in the leftover letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for deposit that I've seen before include "Put down - leave behind" , "Lay down" , "I posted (anag.)" , "Sediment or bank lodgment" , "store" .)