Shoulder-fired missile
A shoulder-fired missile, shoulder-launched missile or man-portable missile is a projectile fired at a target, small enough to be carried by a single person, and fired while held on one's shoulder. The word missile in this context is used in its original broad sense which encompasses all guided missiles and unguided rockets. In many instances, although not technically defining all shoulder-fired missiles, the name Bazooka is used as an informal name regularly, although the actual Bazooka is a type of original shoulder-fired missile in its own right.
Types
There are two kinds of shoulder-launched weapons. The first is the recoilless gun, which is essentially an open tube. When fired the reaction gases (with a momentum equal to the projectile) expelled out of the back of the weapon compensate the force exerted on the projectile.
The other type is the rocket-propelled grenade; these typically also use a small recoilless charge or compressed gas system to get the projectile out of the barrel and to a distance where the operator will not be hurt by the rocket's backblast; when the rocket ignites at a safe distance, it further accelerates the projectile or at least keeps it from decelerating in its trajectory.