In modern parlance, the word 'chronograph' is used to refer to a timepiece which, along with telling the time, serves to measure short times using at least one additional hand. The latter can be started, stopped and reset to zero without disturbing the smooth running of the movement, by means of a control system, generally composed of pushbuttons. If the chronograph function is not associated with a watch as such, the instrument is simply referred to as a timer (or sometimes a stopwatch).

Technically speaking, the chronograph mechanism can be either built into the watch movement, or mounted on the latter in the form of an add-on module. A significant step was taken in 1816, when Parisian horologist Louis Moinet developed what he called a compteur de tierces.