The 8.8 cm Flak 18/36/37/41, better known as the Flak 88, was an anti-aircraft and anti-tank artillery gun employed by Nazi Germany from 1936 to 1945. The word flak comes from the German abbreviation for "airplane defense cannon", and its sounds led to the Germans nicknaming it Acht-acht (88), while the Allies nicknamed it "Ack-ack". 33,600 Flak 88s were produced during World War II, as it was the most popular German anti-tank and anti-aircraft artillery weapon.