AEG - Means auto electric gun and is usually used to refer to an airsoft rifle, carbine, or smg which is powered by batteries and an electiric motor. Thes guns are fully automatic.
GBB - Gas blow back. An airsoft pistol which uses green gas and has a "blow back" effect. Blow back means that the slide of the gun shoots back each time the gun is fired, like in a real pistol.
FPS - Feet per second. This is the velocity at which an airsoft gun can fire a BB. Velocity usually ranges from around 200 FPS to 500 FPS.
