Safekeeping of gold in field of action (7)
I believe the answer is:
storage
'safekeeping' is the definition.
(thesaurus)
'gold in field of action' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'in' is an insertion indicator.
'field of action' becomes 'stage' (I can't justify this - if you can you should believe this answer much more).
'or' placed inside 'stage' is 'STORAGE'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for storage that I've seen before include "What repository provides; so great (anag.)" , "Depository space for goods" , "Stowage" , "reservation?" , "safekeeping" .)