Opera in outdoor setting (4-3)
I believe the answer is:
open-air
'setting' is the definition.
(I have seen 'natural setting' mean 'open air' so perhaps 'setting' could also mean 'open air')
'opera in outdoor' is the wordplay.
'opera in' can be anagrammed to 'OPEN AIR'.
Though, I am unsure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for open-air that I've seen before include "Alfresco" , "outside" , "not below roof" , "Outdoor" , "Taking place outdoors" .)