Ack Ack commonly refers to the artillery fire of anti-aircraft warfare, derived from the initials "AA". Anti-aircraft warfare is the counter to aerial warfare and it includes "all measures designed to nullify or reduce the effectiveness of hostile air action" (NATO's definition). It includes surface based, subsurface (submarine launched), and air-based weapon systems, associated sensor systems, command and control arrangements, and passive measures ( barrage balloons). It may be used to protect naval, ground, and air forces in any location. However, for most countries, the main effort has tended to be homeland defense.

The first application came in the American Civil War. The use of balloons by the U.S. Army during the American Civil War compelled the Confederates to develop methods of combating them. These included the use of artillery, small arms, and saboteurs. .

Turks carried out the first ever anti-airplane operation in history during the Italo-Turkish war. Although lacking anti-aircraft weapons, they were the first to shoot down a plane by rifle fire. The first aircraft to crash in a war was the one of Lieutenant Piero Manzini, shot down on August 25, 1912.

The earliest known use of weapons specifically made for the anti-aircraft role occurred during the Franco-Prussian War of 1870. Gustav Krupp mounted a modified 37 mm gun on top of a horse-drawn carriage for the purpose of shooting down balloons.

More Info: en.wikipedia.org