Dispensing Pump [1]

The original gasoline station pumps were truly pumps. By working a hand lever on the side, the operator created a vacuum in the interior pumping unit and this, in turn, "pulled" product up from the storage tank below. Later, electric motors operated suction pumps [2], with the pumping unit located inside the dispensing device on the pump island [3].

In most modern gasoline stations, the actual pumping unit is not located in the dispenser. Rather, it is located in a remote position, within the storage tank. 

The mechanism located on the pump island, therefore, is not really a pump. It is, rather, a dispenser [4]. It contains a meter, electronic controls, a length of hose with a nozzle on the end, and quite probably a filtering element. 

However, the piece of equipment on the pump island continues to be referred to by many people as a "pump" or a "gas pump." To accommodate this usage, it has become common, within the industry, to speak of the dispenser as a "dispensing pump," although "dispenser" is more accurate.