Propulsive efficiency is the ratio of the aircraft power to the power out of the engine
Defined as the net rate of energy out of the engine divided by the rate of thermal energy available engine
the velocity, relative to a rocket, at which exhaust gases leave the nozzle of the rocket's engine.
The pressure on a surface at which a flowing fluid is brought to rest in excess of the pressure on it when the fluid is not flowing.
Thrust-specific fuel consumption is the fuel efficiency of an engine design with respect to thrust output