An electrode through which charge carriers (holes or electrons) are forced to enter the high-field region in a spacistor.

1. An apparatus containing a nozzle in an actuating fluid which is accelerated and thus entrains a second fluid, so delivering the mixture against a pressure in excess of the actuating fluid.

2. A plug with a valved nozzle through which fuel is metered to the combustion chambers in diesel- or full-injection engines.

3. A jet through which feedwater is injected into a boiler, or fuel is injected into a combustion chamber.