lightning conductor (UK) is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning
strike. If lightning targets the building it will preferentially strike
the rod and be conducted to ground through the wire, instead of passing
through the building, where it could start a fire or cause
electrocution.
A lightning rod is a single component in a lightning protection system. Lightning rods are also called finials, air terminals or strike termination devices.
The lighting rod requires a connection to earth to perform its
protective function. Lightning rods come in many different forms,
including hollow, solid, pointed, rounded, flat strips or even bristle brush-like: copper or aluminum. The main attribute of all lightning rods is they are conductive.