A gun that fires pellets using compressed air
An air gun is a rifle (air rifle), pistol (air pistol), or shotgun that fires projectiles by means of compressed air or other gas, in contrast to a firearm, which burns a propellant. Most air guns use metallic projectiles as ammunition. Some others use arrows. Air guns that only use plastic projectiles are classified as airsoft guns.
Not a firearm but a gun that uses compressed air or CO2 to propel a projectile. Examples: BB gun, pellet gun, CO2 gun.
A loose term applied to any rifle or pistol that uses some form of compressed gas as the propellant.
a gun that propels a projectile by compressed air