And she's not referred to as Anna Karenin because in Russian, the last names are always reflective of the person's gender. Therefore, Karenina.
That, I think I knew. But in the book itself, she's not
ever referred to as "Anna Karenina." And I was LOOKING. Instead, she was either referred to as "Mrs. Karenin, or a couple of times as "Anna Arkadyevna"--or something like that (can't remember exactly), and I couldn't figure out WHERE that name had come from AT ALL.