The term air defence was probably first used by Britain when Air Defence of Great Britain (ADGB) was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called 'anti-aircraft', abbreviated as AA, a term that remained in general use into the 1950s. After the First World War it was sometimes prefixed by 'Light' or 'Heavy' (LAA or HAA) to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery; "ack-ack" (from the spelling alphabet used by the British for voice transmission of "AA"); and archie (a World War I British term probably coined by Amyas Borton and believed to derive via the Royal Flying Corps from the music-hall comedian George Robey's line "Archibald, certainly not!").
Try to answer this question if possible (otherwise reply "unanswerable"): What does ADGB stand for?
Air Defence of Great Britain