A
lightning rod (
US,
AUS) or
lightning conductor (
UK) is a
metal rod or metallic object mounted on top of an elevated structure, such as a
building, a
ship, or even a
tree,
electrically bonded using a wire or
electrical conductor to interface with
ground or "earth" through an
electrode, engineered to protect the structure in the event of
lightning strike. If lightning hits the structure, it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the structure, where it could start a fire or cause
electrocution. Lightning rods are also called
finials, air terminals or strike termination devices.