- a timepiece fitted with a recording device, as a stylus and rotating drum, used to mark the exact instant of an occurrence, especially in astronomy.
- a timepiece capable of measuring extremely brief intervals of time accurately, as a stopwatch able to record fractions of a second as well as elapsed time.
- to time by means of a chronograph.
- an accurate instrument for recording small intervals of time
- any timepiece, esp a wristwatch designed for maximum accuracy
