So technically Orochimaru never died.
If I am correct, even after he was absorbed by Sasuke; Orochimaru was still very much alive. He was able to see and hear everything that was happening outside but simply could not speak or be seen. I am pretty sure if someone can do the above than he/she isn't dead.
He did not die when he was sealed by Itachi. There was still a part of his consciousness inside Anko. I am going to take an example from Harry Potter. Even after Voldemort was "killed" when his spell backfired on him, he still managed to survive because there were part of his consciousness in the Hocrux. Nobody started saying "Voldemort has died once but is still alive".
Simply because Orochimaru did not have any form after he was sealed by Itachi did not mean that he had died.
