Watch glossary

Acrylic Glass

Glass-like product made from polyacrylic esters.

It is highly break resistance and is resistant to weather and corrosion. Small scratches can easily be polished out.


Sensitive to magnetic field interference up to a certain level.

Devices or equipment, the functions of which are protected from magnetic interference by the use of suitable materials and/or screening up to a specified level, are antimagnetic.


When light hits a glass surface it splits in two: one part of the light is bounced back as a reflection, the other goes into the glass. Reflections severely impair the readability of a watch; they reduce both the light permeability of the crystal and also the clarity of the image. Diffuse points of light and reflected images in non-antireflective glass can in some cases be more dominant than the dial itself.

A very thin coating of a suitable translucent material is used to make glass anti-reflective. This coating is generally vapor deposited onto the glass in a vacuum. The splitting of the light mentioned above then takes place both on the surface of the glass and also on the surface of the thin anti-reflective layer. The light reflected from this layer overlaps with that from the glass itself. The layer needs to be thick enough for the light reflected from the different surfaces to cancel each other out through destructive interference. Destructive interference, in simple terms, is when two opposing waves are offset so that the peak of one wave always coincides with a trough of the other, thereby cancelling each other out. Such a displacement occurs because the light reflected from the surface of the glass has to travel slightly further than that from the surface of the coating to ensure overlapping. A further precondition for mutual cancellation is that both waves must have the same amplitude. Multiple layers with different types of coating and thicknesses are required to create an anti-reflective effect at different wavelengths (colours) of visible light.


Physical unit of pressure, i.e. force per surface area.

1 bar = 100 kPa = 0,1 MPa

One bar corresponds roughly to the average atmospheric air pressure at sea level. Water (hydrostatic) pressure increases by approx. one bar for every 10 m of water depth. A watch is therefore subjected to one additional bar for every 10 m of diving depth (quod vide pressure resistance and water-resistance).
1 bar corresponds roughly to the weight of 1 kg per cm² (1 bar = 10 N/cm²). The precise value depends on the location on Earth. The gravitational acceleration varies between 9.78 and 9.83 m/s² Taking the mean value (9.81) as the basis, 1 bar corresponds to a weight of 1019.4 g per cm² .


A chronograph is a timepiece with a stop mechanism which can be used to time the length of a particular procedure.

Divers Bezel

A minute-clicking bezel which can only be rotated on one side to prevent accidental adjustment. It should also be possible to set a diver’s bezel when wearing gloves. Besides the main marking (e.g. luminous triangle) there may also be a minutes scale running clockwise.


The part of a watch movement which periodically inhibits uncontrolled running of the tensioned gear train, thereby ensuring smooth running.

The escapement also supplies new energy to the oscillation system (hairspring), compensating the inevitable friction losses. Modern watches generally contain the Swiss anchor escapement. This works on the principle of an anchor interacting with an escape wheel. The escape wheel intervenes directly in the seconds wheel, onto the shaft of which the seconds hand is fastened. The to-and-fro oscillation of the balance causes the anchor to rock back and forth. As a result it periodically intervenes with its ruby pallets in the escape wheel, blocking its rotation for a short period, before releasing it again for a short time (during the rocking motion). In one second, therefore, there are eight small steps of the seconds hand (at a half-oscillation rate of 28,800/h).


The luminescence phenomenon exploited by daylight luminous paints.

Ordinary paints reflect some of the sunlight or artificial light falling upon them, making them visible to the human eye. In addition to simply reflecting light, daylight luminous paints, by contrast, also emit light, giving these paints their characteristic brightness. The effect is familiar from highlighter pens.
Fluorescent paints only emit this extra light when they are exposed to a light source. Tiny afterglow effects (lasting millionths of a second) which occur as a result of fluorescence cannot be perceived by the eye. By contrast, the luminous paints used to make the dials, hands or luminous triangle glow in the dark exploit the effect of phosphorescence.


Greenwich Mean Time. The astronomically defined local time in Greenwich which was adopted as world time.

GMT was established at the so-called "Meridian Conference" held on 1 October 1884 in Washington. On that day 25 countries agreed upon a binding time zone regulation to provide help to international shipping in particular. Ever since, the Earth has been divided into 24 time zones; adjacent zones differ by exactly one hour (apart from a few exceptional cases). The zero meridian runs through Greenwich (near London). This time zone was defined as the standard world time, GMT or Greenwich Mean Time.

The individual times were defined as astronomical local times, meaning that GMT, in contrast to UTC, is an astronomically based time. One second was defined as one 86400th of the mean solar day, and 12:00 o'clock noon as the sun's highest point. Starting from zero, the meridians are numbered in ascending order to the east and the west, up to the 180° meridian. The 180th degree of longitude divides two days from one another, which is why it is also known as the dateline.

In practice, however, this theoretical zone division is not actually adhered to. Whereas Russia, for example, is divided into several time zones, China only uses one single zone although it stretches over roughly 60 degrees of longitude. The time zone in which a country lies, and how many time zones it covers, are also political decisions.

The letters GMT or UTC on watches indicate that a second time zone can be read off.


Type of light radiation which is not caused by the temperature-specific thermal radiation of a body.

The sun or the coiled filament of a conventional light bulb emit light as the result of their being at a sufficiently high temperature, whereas in luminescent substances it is other processes which generate light by "cold" means. Two variations of luminescence which are of significance for technical applications are phosphorescence and fluorescence. In both cases, the "cold" radiation of light, i.e. luminescence, is caused by the incidence of an appropriate form of artificial light or sunlight. The underlying effects are closely related and can only be distinguished by referring to complex physical phenomena. However, given that phosphorescent pigments are designed to glow for longer periods (hours) whereas fluorescent pigments are not, it can be said in simple terms that daylight luminous paints are the product of fluorescence, whereas afterglow effects are basically caused by phosphorescence.


Forces which can commonly be observed in the form of magnetized objects attracting and repelling each other. Possible source of interference in a watch’s action.

Magnetic fields are encountered with ever-increasing frequency in our environment. Whereas the Earth’s magnetic field does not constitute a risk, magnetic fields from loudspeakers, door closers, locks etc. can have a lasting effect on the action of a mechanical watch. In a survey of almost 1000 watches carried out by SINN’s customer service department, roughly 60% of these proved to be magnetized, and half of these, i.e. 30% of the total, exhibited strong magnetic field errors. In some cases the accuracy errors could be corrected by demagnetizing them.

The main source of magnetic field errors lies in a magnetized Nivarox hairspring, i.e. the timing organ of the watch. Nivarox hairsprings are far superior to older steel springs with regard to magnetic field sensitivity, as Nivarox springs are antimagnetic (DIN 8309). However this requirement permits an error margin of +/- 30 seconds per day under exposure to relatively weak magnetic fields. This, though, is not compatible with chronometer standards.


Unsusceptible to the influence of magnetic fields up to a defined strength.

Strictly speaking, no material is completely unaffected by magnetic fields. Materials or objects are described as non-magnetic if they react so minimally to magnetic fields that sensitive instruments are needed in order to detect any effect. For all practical purposes, materials such as glass or some types of steel can be rated non-magnetic.


Watch equipped with a quartz movement.

Quartz watches were developed and built for the first time in the first quarter of the 20th century. Based on a more affordable production technology, they conquered the market in the late 1970s.
While you can actually observe the clockwork mechanism of a watch in action, the function of a quartz watch is based on electronic processes which, for the most part, are not directly visible. While the physical oscillation of the timepiece is also visible in the centre of the quartz movement – that is, the oscillating crystal – this oscillation is so slight and so fast that it is invisible to the naked eye. What’s more, the oscillating crystal is positioned inside a capsule, which allows it to oscillate shielded in a protective gas.
The basic principle behind quartz oscillation is the (inverse) piezo effect, which refers to the visible formation of crystals in many materials following the application of an electric charge. Inside the movement, such a piezoelectric element is integrated into an electronic oscillator, which generally operates at a frequency of just over 32,000 Hz. Through continued frequency division, the second interval is derived from this high frequency, ultimately actuating the stepper motor. In the case of analogue quartz watches, the stepper motor generates the typical jerking movement of the second hand using the gear train.
Due to their high frequency, quartz movements are much more precise than mechanical movements. Unlike temperature-compensated chronometer movements, conventional movements demonstrate a deviation of a few seconds per week. They’re powered by electric energy, which is generally provided in the form of a button cell and can power a quartz movement for approximately two years. Just like mechanical movements, quartz movements also feature special constructions, drawing their energy from a barrel or a rotor. Lithium batteries and especially energy-efficient motor controls, such as those in our UX and 434 models, deliver a much longer service life.
Complications, chronographs and perpetual calendars can be incorporated into quartz watches without much effort, as the corresponding displays are powered by separate motors and the associated controls are easy to program using the integrated circuits.


The stages involved in achieving that highest possible degree of accuracy in a watch.

Even though the production quality of toothed wheels, bearings and pivots is decisive for the stable running of a watch, these manufacturing stages are not generally regarded as part of the regulation system.

However, the regulator correction at the end of the regulation process, which is often the most visible aspect of regulation, can only succeed as part of a good overall regulation process.

Regulation is an adjustment procedure carried out in four stages: centering the hairspring, adjusting the escapement, truing the balance, adjusting the regulator.

Regulation can cover both the different test positions and also temperatures. This is required in particular in the regulation of a chronometer.

Regulator Correction

A device used to set the rate of a watch.

A regulator correction changes the effective spring length of the oscillation system’s hairspring. Before the hairspring hits its outer fixture point it passes through a gap formed by two adjacent pins. The part of the spring between the gap and the outer fixture point is exempted from the free oscillation of the spring. If the position of the gap is shifted by a regulator correction, this changes the active spring length. Depending on the direction of the change, the watch then runs faster or slower.


A chemical element belonging to the group of platinum metals.
Rhodium is a precious metal that is difficult to extract, and is comparable to platinum in many respects. Jewellery designers often use rhodium to give white-gold alloys a decorative finish.

Sapphire Crystal

Watch glass made from artificially produced sapphire crystal. Sapphire crystal consists of monocrystalline aluminum oxide (Al2O3). At 2000 HV on the Vickers hardness scale, it is a scratch-resistant watch glass. It is also considerably more scratch-resistant than mineral glass.

Seconds Stop Function

Device to stop the watch movement, allows precise setting of the time.

The seconds stop function needs to be distinguished from the stopwatch second function. The stopwatch second function is operated by pressing a push-piece; this allows times to be stopped using a separate display without having to lose the current time as a result. This function is reserved exclusively for chronograph movements. The seconds stop, by contrast, is also incorporated in three-hand movement watches (hours, minutes, seconds) and is triggered by pulling the crown into the setting position. A lever mechanism linked to the crown arrests the balance oscillation right at the balance wheel, stopping the movement immediately. Once the hands have been adjusted, the watch can then be restarted with split-second accuracy using a reference time signal.

Shock Resistance

As of mid-2017, watches must meet the requirements of the DIN ISO 1413 standard to obtain the ‘shock-resistant’ label. The former DIN 8308 standard is therefore no longer applicable.

The DIN ISO 1413 standard expands on the DIN 8308 requirements and tightens some of the test criteria. It represents a continuation of the fundamental concept that a fall from a height of 1 metre onto a hard wooden floor should not damage the function of a shock-resistant wristwatch and that any resulting change in the watch rate should not exceed +/–60 seconds per day.

Like its predecessor, the DIN 8308 standard, the DIN ISO 1413 standard simulates the conditions of the free fall with a hammer blow at a specified speed and with certain material specifications, so that the test can be conducted under clearly defined, repeatable conditions.

Key new aspects of the DIN ISO 1413 standard are attention to hand position and the introduction of an additional shock to the crown.

Slide-Rule Scale

The slide-rule scale works on the principle of logarithmic scale divisions. This allows you to multiply and divide numbers. It is useful for calculating consumption, converting units and currencies and for all kinds of rule-of-three calculations.

Split-Seconds Hand

An additional second hand on a stopwatch/chronograph for recording intermediate times.
With a split-seconds chronograph (also called a rattrapante), two second hands are set in motion when the start button is pressed. The specific split-seconds function now makes it possible to stop the second stopwatch hand (the ‘carried’ hand) separately, without affecting the movement of the other second hand. In this way, an intermediate time can be recorded. The split-seconds hand can be re-synchronised with the first second hand by pressing the intermediate stop button again.

Stainless Steel

Stainless steel is a grade of steel with a very high degree of purity and a chemical composition defined within narrow tolerances.

Of particular importance in watchmaking are corrosion-resistant stainless steels, i.e. types of steel which are protected from corrosion.


Luminous paint for dials and hands, belonging to the group of inactive luminous paints, i.e. it emits no radiation. The luminous effect is based on the principle of phosphorescence.

Superluminova therefore needs to be charged by an external light source. In order to exploit the maximum luminous capacity of the paint pigments, the paint must first be fully activated. In direct sunlight this takes roughly 90 minutes. Superluminova can be charged and discharged as often as required without losing any of its charging capacity. A further advantage in comparison to tritium-based radioluminescent paint is that it does not turn gray or yellow with age.

Tachymeter Scale

The tachymeter scale permits an average speed to be measured over a distance of one kilometer. For this, the stop-watch function must be activated at the start and end of the distance. Miles per hour (mph) can also be measured using the tachymeter scale and the same principle.

Water Resistance

Water Resistance

The ability to retain a seal when submerged in increasing depths of water, expressed as a rating of depth in metres (m) or pressure in Atmospheres (ATM).