Impeller. Impeller is a rotor used to increase the kinetic energy of the flow.
Casing (Volute). The casing contains the liquid and acts as a pressure containment vessel that directs the flow of liquid in and out of the centrifugal pump.
Shaft (Rotor). The impeller is mounted on a shaft. Shaft  is a mechanical component for transmitting torque from the motor to the impeller.
Shaft sealing. Centrifugal pumps are provided with packing rings or mechanical seal which helps prevent the leakage of the pumped liquid.
Bearings. Bearings constrain relative motion of the shaft (rotor) and reduce friction between the rotating shaft and the stator.