Bazooka was first the name of a musical instrument, and later also that of an anti-tank weapon and a brand of chewing gum.
The bazooka is a folk musical instrument, a rather primitive version of a trombone, usually with a lower but less wide range. From the mouthpiece the air chamber goes into wide lengths of pipe of sizes so that the wider diameter pipe can slide around the narrower one, lengthening or shortening the instrument to change the pitch. The bazooka was popularized in the 1930s by radio comedian Bob Burns, who may have invented the instrument some 20 years earlier. The bazooka was also played by jazz musician Noone Johnson.
The bazooka weapon was one of the first anti-tank weapons based on the HEAT shell to enter service, used by the United States Armed Forces in World War II. It was nicknamed a "bazooka" from a vague resemblance to the musical instrument. It was highly effective, so much so that the Germans copied it outright to produce their own version known as the Panzerschreck. The bazooka could be found in all theatres of war during World War II, and was used until the Korean War when it was then replaced by newer weapons such as the LAW in time for the Vietnam War.
Prior to the war the US Army had developed a shaped-charge hand grenade for anti-tank use that was effective at defeating up to 100mm of armor, by far the best such weapon in the world at the time. However it remained very difficult to use, requiring it to be placed directly on the tank, and for this reason it was largely ignored.
Things changed when Colonel Skinner suggested placing the grenade on the front of his experimental rocket launcher, which was a weapon looking for a role. This proved to be a good match, and by late 1942 the Rocket Launcher, M1A1 was introduced. This consisted of a long (4ft) tube with a simple wooden stock and sights, into which the 60mm rocket grenades were inserted at the rear. A small battery provided a charge to ignite the rocket when the trigger was pulled. The main drawback to the weapon was the large backblast and smoke trail which gave away the position of the shooter.
In 1944 the M1A1 model was supplemented by the improved M9 and then the M9A1 which could be broken into two halves for easier carrying. A larger 3.5lb warhead was under development, but didn't reach service until after the war had ended. By the time of the Korean War an even larger M20 with a 2lb 3.5" warhead was starting to enter service, which could penetrate well over 200mm of armor and had an extended range of about 150m.
During World War II, The Topps Company marketed a brand of bubblegum under the name Bazooka. The gum was packaged in a patriotic red, white, and blue color scheme, although Topps claims that it took the name from the instrument, not the weapon. Beginning in 1953, Topps changed the packaging to include small comic strips with the gum, featuring the character "Bazooka Joe".