Theatre PR resolved to produce description of trilogy (5-4)
I believe the answer is:
three-part
'produce description of trilogy' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'theatre pr resolved' is the wordplay.
'resolved' indicates anagramming the letters.
'theatre'+'pr'='theatrepr'
'theatrepr' with letters rearranged gives 'THREE-PART'.
'to' acts as a link.
Can you help me to learn more?
(Another definition for three-part that I've seen is " (Of work) composed for a trio of voices".)