An automatic chronograph is a type of watch dependent exclusively on kinetic energy as its power source. "Chronograph" is defined as something that records time. In more modern watches, this references some sort of stopwatch function incorporated into a watch.
An automatic chronograph is contrasted with a digital chronograph. A digital chronograph relies upon a battery as its primary power source. "Chronograph" is associated with the word "chronometer." Technically, a chronometer is anything capable of keeping track of time, from a sundial to a watch. In more modern times, the use of chronometer is more typically associated with a highly accurate timepiece.