What is an impeller?

The impeller is the rotating vaned disc inside a pump housing. In a washer or dishwasher drain pump it is the part that debris jams against — a sock, a fruit sticker or a shard of glass wedged between the vanes stops the pump dead while the motor keeps humming. On top-load washers the word is also used for the low-profile wash plate that replaces a tall agitator.