State sector briefly featuring in vocal piece (7)
I believe the answer is:
arizona
'state' is the definition.
(Arizona is a US state)
'sector briefly featuring in vocal piece' is the wordplay.
'sector' becomes 'zone' (I've seen this before).
'briefly' means to remove the last letter.
'featuring in' means one lot of letters goes inside another.
'vocal piece' becomes 'aria' (aria is a kind of piece. I am not sure about the 'vocal' bit.).
'zone' with its final letter taken off is 'zon'.
'zon' inserted inside 'aria' is 'ARIZONA'.
Can you help me to learn more?
(Other definitions for arizona that I've seen before include "American state with Grand Canyon" , "State of southwest USA" , "part of US" , "Dry US state" , "State of southern US" .)