Bank's strongroom (5)
I believe the answer is:
vault
'bank's strongroom' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for vault that I've seen before include "Leap; storage chamber" , "Secure room in bank" , "Leap - wine or money chamber?" , "Burial chamber - jump across" , "Where bodies may be kept" .)