Customary part for soprano put on line (6)
I believe the answer is:
normal
'customary' is the definition.
(I've seen this in another clue)
'part for soprano put on line' is the wordplay.
'part for soprano' becomes 'norma' (I can't explain this - if you can you should believe this answer much more).
'put on' says to put letters next to each other.
'line' becomes 'l' (used when specifying particular lines from a poem).
'norma'+'l'='NORMAL'
Can you help me to learn more?
(Other definitions for normal that I've seen before include "Usual, typical, expected" , "Standard - well-adjusted" , "Usual - sane" , "'Usual, typical (6)'" , "Unexceptional" .)