Domains concerned with charitable donations (6)
I believe the answer is:
realms
'domains' is the definition.
('realm' can be a synonym of 'domain')
'concerned with charitable donations' is the wordplay.
'concerned with' becomes 're'.
'charitable donations' becomes 'alms' (I've seen this before).
're'+'alms'='REALMS'
(Other definitions for realms that I've seen before include "Fields of activity or interest - sound monarchical" , "Kingdoms, or fields of interest" , "Kingdoms, or fields of activity" , "Domains ruled by king or queen" , "Kingdoms, domains" .)