Prima donna's solo (4)
I believe the answer is:
aria
'prima donna's solo' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aria that I've seen before include "Operatic tune" , "Operatic vocal" , "Operatic song" , "Song for solo voice from an oratorio, cantata etc" , "Operatic number" .)