adjective. Designed for defense, especially from a surface position, against aircraft or missile attack.

noun. An antiaircraft weapon.

adjective. Intended to attack aircraft.

noun. Antiaircraft artillery.

noun. An antiaircraft artillery organization.

noun. Antiaircraft fire.

"I had a 26-inch IC barrel for pheasant, and I provided entertainment for zig-zagging doves by wasting a few boxes in "antiaircraft fire", but the best I ever shot at the skeet range was 19 out of 25 with a borrowed Franchi O/U 20 gauge!"

aircraft  

AA  AAA  ack-ack  air defence  air defense