Head: refers to the energy obtained when unit weight of the liquid through the pump, the lift is also called the total head or head, with H said and the unit is meter.
Flow: refers to the amount of liquid supplied by the pump per unit of time, expressed in Q, in meters per hour or liters per second.
The number of revolutions: that is the number of revolutions of the pump in minutes, expressed in n, in revolutions per minute.
Shaft power: that is the power transmitted by the prime mover to the pump shaft, expressed in N, in kilowatts or horsepower.
Efficiency: shaft power is not all used by the pump and part of that has lost.