|lightning conductor or lightning rod|
|a metal strip terminating in a series of sharp points, attached to the highest part of a building, etc, to discharge the electric field before it can reach a dangerous level and cause a lightning strike|
|lightning rod or lightning rod|
A grounded metal rod placed high on a structure to conduct electrical current from a lightning strike directly to the ground, preventing the currents from injuring people or animals or from damaging objects. Lightning rods usually have a sharp, pointed tip, since electric lines of force are more highly concentrated around pointed objects, in this case increasing the attractiveness of the rod compared with other nearby objects. See also Saint Elmo's fire.
lightning rod definition
metallic rod (usually copper) that protects a structure from lightning damage by intercepting flashes and guiding their currents into the ground. Because lightning tends to strike the highest object in the vicinity, rods are typically placed at the apex of a structure and along its ridges; they are connected to the ground by low-impedance cables. In the case of a building, the soil is used as the ground; on a ship, the water is used.
Learn more about lightning rod with a free trial on Britannica.com.