Melodic Melba (6)
I believe the answer is:
nellie
'melodic melba' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nellie that I've seen before include "Old song: ''Wait Till the Sun Shines . . . . . .''" , "Elephant in a song" , "Girl" , "Dame -- Melba, singer" , "'There's an old mill by the stream, . . . . . . Dean'" .)