Part of Hungarian song (4)
I believe the answer is:
aria
'song' is the definition.
(piece of music in an opera)
'part of hungarian' is the wordplay.
'part of' indicates a hidden word.
'ARIA' is hidden in the letters of 'hungarian'.
(Other definitions for aria that I've seen before include "Operatic number" , "Operatic song" , "Operatic part" , "Puccini item" , "Operatic solo performance" .)