When the Pump, Gas Booster, Air amplifier has reached its, that is, the drive force is equal to the sum of the resistance pressure force and the friction in the (pump , gas , air amp,) section. Under this condition, there is no of forces left to drive the unit, and it stops cycling. This condition is referred to as 'stall'.

ETYM Old Eng. stal, as. steall, stall, a place, seat, or station, a stable.
1. A compartment in a stable where a single animal is confined and fed.
2. A place where articles are displayed for sale; SYN. stand, sales booth.
3. A malfunction in the flight of an aircraft in which there is a sudden loss of lift that results in a downward plunge.
4. A tactic used to mislead or delay; SYN. stalling, delaying.

The condition of an airfoil or aircraft in which excessive angle of attack causes disruption of airflow with attendant loss of lift

ETYM as. steallian to have room. Related to Stall.
1. To deliberately delay an event or action.
2. To cause an engine to stop.
3. To come to a stop; SYN. conk.
4. To cause an airplane to go into a stall.
5. To experience a stall in flight, of airplanes.