Start of marvellous song, one sung in 'West Side Story' (5)
I believe the answer is:
maria
'one sung in west side story' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'start of marvellous song' is the wordplay.
'start of' suggests taking the first letters.
'song' becomes 'aria' (aria is a kind of song).
The initial letter of 'marvellous' is 'm'.
'm'+'aria'='MARIA'
Can you help me to learn more?
(Other definitions for maria that I've seen before include "- Callas, twentieth century opera singer" , "(Of plant) become limp" , "More than one plain" , "Italian Mary" , "Lunar plains; girl's name" .)