That event (or events) in a series of events in an accident that determined the exact time, place, type, and extent of consequence of the accident.

A term used to describe the reaction of a piece of material (usually wood) when being cut by a circular saw which is rotating in the opposite direction from the material as it is fed into the saw. Since the saw blade is rotating at a high rate of speed the force that can be exerted on the material is substantial and can cause serious injury to the operator.