A timepiece is a device used to measure and keep track of time. TIMER, CHRONOMETER, WATCH, CLOCK, wristwatch, EON, horloge, and stemwinder are all terms used to describe different types of timepieces. A TIMER is a device that can be set to count down a certain amount of time. A CHRONOMETER is an instrument used to measure time accurately. A WATCH is a small timepiece worn on the wrist or carried in a pocket. A CLOCK is a device that measures and displays time. A wristwatch is a type of WATCH that is worn on the wrist. An EON is an indefinitely long period of time. A horloge is a type of CLOCK that is powered by weights or springs. A stemwinder is a type of WATCH that is wound by turning a knob on the stem.