Party at chief's estates (7)
I believe the answer is:
domains
'estates' is the definition.
The definition and answer can be both groups as well as being plural nouns.
Perhaps there's an association between them I don't understand?
'party at chief's' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'at' is a charade indicator (letters next to each other).
'chief's' becomes 'main's'.
'do'+'mains'='DOMAINS'
Can you help me to learn more?
(Other definitions for domains that I've seen before include "Areas" , "Realms" .)