ack-ack

English

ack-ack gun emplacement c. 1941

Etymology

From ack (“A”) + ack (“A”), RAF WWI signalese for AA (“anti-aircraft”). (In modern signalese it would be called alpha-alpha.)

Noun

ack-ack (countable and uncountable, plural ack-acks)

1. Antiaircraft artillery.

   The army fired upon us with ack-ack.

   Ack-acks were set up in the square.

   • 2015, Kate Atkinson, A God in Ruins, →ISBN, page 140:

     He had thought how down there on the ground, on enemy soil, there were probably hundreds of Ivys, nice Fräuleins with buck teeth and fiancés on U-boats, manning the German ack-ack, all united in an effort to kill him.

2. (uncountable) Antiaircraft fire

   The bomber flew through heavy ack-ack.

Synonyms

• (anti-aircraft gun): AAA, AA

References

• “ack-ack”, in OneLook Dictionary Search.
• ack-ack on Wikipedia.Wikipedia