Elephant in a song (6)
I believe the answer is:
nellie
'elephant in a song' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nellie that I've seen before include "Old song: ''Wait Till the Sun Shines . . . . . .''" , "Girl" , "'There's an old mill by the stream, . . . . . . Dean'" , "See 6" , "Elephant in a song" .)