A missile is an airborne ranged weapon capable of self-propelled flight aided usually by a propellant, jet engine or rocket motor.
Historically, 'missile' referred to any projectile that is thrown, shot or propelled towards a target; this usage is still recognized today with any unguided jet- or rocket-propelled weapons generally described as rocket artillery. Airborne explosive devices without propulsion are referred to as shells if fired by an artillery piece and bombs if dropped by an aircraft.
Missiles are also generally guided towards specific targets termed as guided missiles or guided rockets. Missile systems usually have five system components: targeting, guidance system, flight system, engine, and warhead. Missiles are primarily classified into different types based on firing source and target such as surface-to-surface, air-to-surface, surface-to-air and air-to-air missiles.
a. An object propelled (either by hand or mechanically) as a weapon at a target
b. Military. A long-distance weapon that is self-propelled, and directed either by remote control or automatically, during part or all of its course.