A watch which not only indicates the time of the day in hours, minutes and seconds, but it also equipped with an additional mechanism - operated manually by push buttons - which makes it possible to measure continuous or discontinuous intervals of time, from a fraction of a second to 12 hours.
Not to be confused with a chronograph, this term is assigned to watches that have undergone thorough and intensive testing at an official laboratory or an official institute. A chronometer is a precision instrument and is accompanied by a certificate.
An instrument, usually a pocket watch, which only measure intervals of time and does not indicate the time of day. A stopwatch can be incorporated into a standard watch; both the stopwatch function and the timepiece would then be referred to as a "chronograph."
A function that lets the wearer keep track of how much of a pre-set period of time has elapsed. Some countdown timers sound a warning signal a few seconds before time runs out - these are usually events such as yacht races, where the sailor must maneuver the boat into position before the start of a race.
A seconds-hand that is mounted in the center of the watch dial.
Determines the distance of an object from the observer by measureing how long it takes sound to travel that distance. Like a tachymeter, it consists of a stopwatch or chronograph, and a special scale, usually on the outermost edge of the watch face. One use of a telemeter would be determining the distance of a storm from its observer.
Probably the most common feature on a chronograph, a tachymeter (also called tachometer) measures the speed at which the wearer has traveled over a measured distance. The wearer starts the chronograph when passing the starting point and stops it when passing the finish. The wearer can then read the speed in units, in this case, miles per hour, off the tachymeter side.
A chronograph function that lets the wearer time segments of a race. At the end of a lap, he stops the timer , which then returns to zero, to begin timing the next lap.
The ability, in some quartz sport watches, to preserve in the watch's memory the times of laps in a race that have been determined by th elap timer (see lap timer). The wearer can recall these times on a digital display by pushing a button.
12 hour recorder (or register)
A subdial on a chronograph (see "chronograph") that can time periods up to 12 hours.
A device that sounds a signal at a pre-set time.
A countdown timer that sounds warning signals during the countdown to the boat race.
A bezel (the ring which holds the crystal) that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions.
Elapsed time rotating bezel
A graduated rotating bezel used to keep track of periods of time. The bezel can be turned so the wearer can align the zero on the bezel with the watch's seconds or minutes hand. He can then read the elapsed time off the bezel. This saves him having to perform the subtraction that would be necessary if he used the watch's regular dial.
Uni-directional rotating bezel
An elapsed time rotating bezel often found on divers watches, that moves only in a counterclock-wise direction. It is designed to prevent a diver who has unwittingly knocked the bezel off its original position from overestimating his remaining air supply. Because the bezel moves in only one direction - the diver can err only on the side of safety when timing his dive. Many divers watches are ratcheted, so they they lock into place for greater safety.
A device, consisting of logarithmic or other scales on the outer edge of the watch face, that can be used to do mathematical calculations. One of the scales is marked on a rotating bezel, which can be slid against the stationary scale to make the calculations. Some watches have slide rules that allow specific calculations, such as for fuel consumption by an airplane.
A seconds hand on a chronograph that can be used to time laps or to determine finishing times for several competitors in a race. Usually has two sweep second hands, one positioned above the other. When the timer is running, the hands appear as one. When the start/stop button is activated while the chronograph mechanism is running, one hand stops to record a lap time etc. and the other continues to run. Activating the start/stop button causes the hand to return to the original position in tandem with the running sweep hand.
Auto repeat countdown timer
A countdown timer that resets itself as soon as the preset time has elapsed and starts the countdown again. It repeats the countdown continuously until the wearer pushes the stop button.
A small dial within a watch dial used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date.