Search Result for "ack-ack": 
Wordnet 3.0

NOUN (1)

1. artillery designed to shoot upward at airplanes;
[syn: antiaircraft, antiaircraft gun, flak, flack, pom-pom, ack-ack, ack-ack gun]


The Collaborative International Dictionary of English v.0.48:

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 [WordNet 1.5 +PJC]
WordNet (r) 3.0 (2006):

ack-ack n 1: artillery designed to shoot upward at airplanes [syn: antiaircraft, antiaircraft gun, flak, flack, pom- pom, ack-ack, ack-ack gun]