rod
"Sign of the rod" means "power", (Psalms 110:2); (Psalms 2:9); (Revelation 2:27). It was Moses' shepherd's crook, the tool of his calling. Cast down, it became a serpent; taken up in faith, it became "the rod of God"; (Exodus 4:20); (Exodus 7:12).
( See Scofield) - (Exodus 7:12)