The Collaborative International Dictionary
ack-ack \ack-ack\ n. [from AA, meaning antiaircraft pronounced ack-ack by British signalmen.] (Mil.) Artillery designed to shoot upward at airplanes; antiaircraft artillery.
Syn: antiaircraft, antiaircraft gun, flak, pompom, pom-pom, ack-ack gun
Douglas Harper's Etymology Dictionary
1939, representing A.A., the military abbreviation for anti-aircraft (see ack).
Wiktionary
a. Of or relating to antiaircraft warfare. n. 1 antiaircraft artillery. 2 (context uncountable English) Antiaircraft fire
WordNet
n. artillery designed to shoot upward at airplanes [syn: antiaircraft, antiaircraft gun, flak, flack, pom-pom, ack-ack gun]
Usage examples of "ack-ack".
We took cover in the sandbagged shelter under the school arches whenever the sirens went and the ack-ack guns began firing at the top af Caulms Wood.
She inspected the two torpedo tubes, sat behind the 20mm ack-ack gun in the fore-deck well and inspected the Bofors gun which had been fitted in the after deck.
Wagner and Bauer were working the Bofors gun on the after deck, tracer streaming up in an arc, following the Junkers as it sped away and Wittig was hammering at it with the 20mm ack-ack gun in the fore deck well.
Several ack-ack lasers begin to open fire on the approach- ing spacecraft.
Liftin' the barrel of a bleedin' ack-ack gun, that's 'ow I got it.
He mounts the podium, dives for a round of chalk, and starts hammering equations onto the blackboard like an ack-ack gun.
Another flash-bang following on its heels, and another, as though an ack-ack gun were going off beneath our feet.
There was a loud hum that threatened to drown out the ack-ack guns, and the veils on the net began to lower.
A Stinger took down another sea-jet off the starboard side, and the Saratoga ack-ack crews combined with those of a frigate to blow the wing off a big Beriev.