Orbit — monarchy (5)
I believe the answer is:
realm
I believe this clue is a double definition.
'orbit' is the first definition.
(I know that realm is a type of orbit)
'monarchy' is the second definition.
(I know that realm is a type of monarchy)
(Other definitions for realm that I've seen before include "Kingdom or sphere" , "Area of influence" , "Royal domain" , "Dominion" , "field of study" .)