Zerahemnah’s Sword is the sword retained by Zerahemnah when Moroni spoke to him. Angry with Moroni, Zerahemnah rushed forward intending to slay him, and raised the sword (Alma 44:12).
One of Moroni’s soldiers “smote it even to the earth,” and the sword “broke by the hilt.” The soldier then smote Zerahemnah, and Zerahemnah withdrew into the midst of his soldiers (Alma 44:12).