Impeller n. : One who, or that which, impels.

Example:
How much would it cost to get my Impeller changed?

Taxonomy
impeller, the fluid, fluid, housing, tanks, radial flow impellers, pump impellers, water jet, free encyclopedia, washing machines, blades, speed, Axial flow, pot, Firefighting, rank, badge, gas turbine engines.

Defination from the web:
impeller is a rotating component of a centrifugal pump, usually made of iron, steel, bronze, brass, aluminum or plastic, which transfers ... The velocity achieved by the impeller transfers into pressure when the outward movement of the fluid is confined by the pump casing. ...