She has many a song in West Side Story (5)
I believe the answer is:
maria
'she' is the definition.
'many a song in west side story' is the wordplay.
'many' becomes 'm'.
'a song in west side story' becomes 'aria' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'm'+'aria'='MARIA'
'has' is the link.
Can you help me to learn more?
(Other definitions for maria that I've seen before include "one from West Side Story" , "Woman" , "Girl's name; darker moon areas" , "musical" , "- Callas, twentieth century opera singer" .)