Rule 14; a procedural device whereby a party, usually the defendant, may bring into a lawsuit another person, asserting that such person is or may be liable to him for all or part of the plaintiff's claim. For example, where plaintiff is made ill by eating bad meat at a restaurant and sues the restaurant, the restaurant may wish to implead the meat processor.
Impleader is a procedural device before trial in which one party joins a third party into a lawsuit because that third party is liable to an original defendant. For example, in a case where a driver rear-ends another car due to faulty brakes, and is sued by the accident victim, the driver may decide to implead the repair shop where the brakes were worked on.