The artifact that lets Ezio receive messages from Minerva in Assassin's Creed II is an Apple of Eden. In the game's finale beneath the Vatican, Ezio encounters the Isu figure Minerva, who communicates through the Apple and addresses a future descendant rather than explaining everything to Ezio directly.
Apples of Eden are Pieces of Eden, technologically advanced artifacts created by the Isu, the precursor civilization known in older lore as the Those Who Came Before. They can influence minds and project information, making them central objects in the Assassin–Templar conflict.
Assassin's Creed II does not treat every Piece of Eden as the same object. The Staff of Eden and Sword of Eden are separate artifacts with different histories, while the Shroud of Eden appears in another storyline. The Apple in Ezio's ending is therefore a specific artifact, not a general name for all Isu technology.