The Bazooka is one of the firsts man portable anti tank rocket launcher and it was developed by the US during the WW II it's also the first this kind of design. A tube housing a rocket in the rear of the gun. It exists in several variants from the M1 up to the improved M20 and variants and some experimental guns such as the M25 three shoot bazooka.
The bazooka in popular culture designates all this Tube launching rocket launchers who houses the rocket inside the tube, the other rival model is called RPG (Rocket Propelled Grenade) and have the rocket located in front of the weapon clearly visible with the rear attached to the launcher. It's popularity came certainly because because it was one of the firsts of its kind and because it was a very successful weapon who proved its efficiency in the battlefields.