Seat of power (6)
I believe the answer is:
throne
'seat of power' is the definition.
(as in a monarch's throne)
This is the entire clue.
(Other definitions for throne that I've seen before include "Seat of monarch" , "Ceremonial chair for bishop or king" , "A king or queen sits on it" , "Seat of a ruler" , "Seat of royal power" .)