Welles's citizen (4)
I believe the answer is:
'welles's citizen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kane that I've seen before include "1941 cinematic citizen" , "Great Orson Welles movie 'Citizen . . . .'" , "Orson Welles's film ` `Citizen ....' '" , "Famous film by Orson Welles 'Citizen . . . .'" , "'Citizen . . . .', great film by Orson Welles" .)