If it was named for a different character, this 1899 Chekhov play would be "Niece Sonya"
[DOC] [TLE] Uncle Vanya (Theatre) - TV Tropes [PAR] One of Anton Chekhov's major plays, Uncle Vanya is a four-act play that deals 
with the ... his wife, Elena; his mother, Maria; his niece, Sonya, and a nurse called 
Marina.