Storage room (5)
'storage room' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for attic that I've seen before include "Top level" , "Upper chamber" , "Ancient Greek; loft" , "Upstairs room" , "Ancient Greek dialect - top room" .)
'storage room' is the definition.
(vault is a kind of storage room)
This is the entire clue.
(Other definitions for vault that I've seen before include "Underground chamber - leap" , "Burial chamber - jump across" , "Spring - clear - cellar" , "Leap - wine or money chamber?" , "Secure room -- spring over" .)