Joined in duet with variations (6)
I believe the answer is:
'joined' is the definition.
'in duet with variations' is the wordplay.
'in duet' anagrams to 'UNITED'.
But, I am unsure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for united that I've seen before include "Joined together as in alliance" , "Joined together as one" , "cooperative" , "See 14" , "See 9" .)