Plunging fire
Plunging fire is gunfire directed upon an enemy from an elevated position, or gunfire aimed so as to fall on an enemy from above.
In naval warfare plunging fire was often used to penetrate an enemy ship's thinner deck armor rather than firing directly at an enemy ship's side. Another method is in a form of indirect fire, by aiming the weapon, usually a machine gun or belt-fed grenade launcher, at such a degree that it is pointed over an elevated obstacle such as a hill that it may nearly graze it. The impact zone will be just that of the opposite side. The trajectory of the rounds will take effect and "plunge" greatly after travelling the determined range; in which the rounds will be falling from directly above vice from the front, increasing the chances of striking an advancing force in the cone of fire when no other technique becomes effective.
Both the howitzer and mortar provide this type of fire.