Glossary of Watch Terms

Altimeter - a device to determine the altitude above sea level by measuring atmospheric pressure.

Aperture - a small hole (window) in the dial of the clock, which gives information about current date, etc.

Atmosphere - pressure in one atmospheric unit (Eng. ATU). Corresponds to sea level pressure. Excess pressure in one atmosphere exists under water at about 10, 33 meters.

Bezel (from Eng. Bezel - a round jack) or limb / lunette - a rotary rim around the dial. It serves to fix time lines. An indispensable attribute for dive watches.

Water resistance – feature of the case to prevent the watch movement from moisture. The level of water resistance is usually measured in meters or atmospheres. A ten meter dip causes pressure increasing per one atmosphere. For the first time this function was implemented by the Rolex Company in 1926.

The crown - a part of the watch case, used to set the watch as well as to change time and date.

Power reserve - the ability of mechanical watch to continue correct work for a certain time without starting the main spring. The electronic watches work from one battery. Expensive watch models come with a power reserve indicator.

Quartz movement  - mechanism that works due to a battery, durable for several years (as a rule, for 3 years). Quartz watches have high accuracy movement, the deviation can be only a few seconds in a month. Quartz watches do not need to be wind. The time-consuming element is a quartz resonator. It is a specially processed plate made of an artificial quartz crystal, which can be compressed under the pressure and as a result generate electrical impulses.

The indicator of the moon’s phase - a dial with a gradation of 29 days and a rotating indicator with the Moon image. At any specific time, the indicator shows the current phase of the moon.

Stones - a term, used to define watch parts made of rubies, sapphires or garnets, both synthetic and natural, which are used to reduce friction between metal parts.

Watch caliber – a diameter of the watch platinum in round watches. In other forms of watches it is a diameter of the disk of the same area as platinum. In the USSR it was measured in millimeters. The industry standard provided 16, 18, 20, 22, 24, 26, 30, 34, 36 and 40 mm, although there were some exceptions. For example, the watch ‘3133’ (‘Shturmanskie’) has platinum with a diameter of 31 mm (2 first digits of the watch). As a rule, manufacturers from Switzerland traditionally measure the caliber of watches in ‘lines’. Many companies call the caliber a size of the mechanism, this way several different Orient models can differ in case, design, but have one movement.

Gilding - covering the case and / or watch bracelet (usually made of steel) with a thin layer of gold. Basically, gilding of 5 and 10 micrometers is more common. Nowadays, the PVD (PhysicalVapourDeposition) coating is widely used in the watch industry. It is when a superhard titanium nitride is applied to the case material in a vacuum, and over it an ultra-thin layer of gold is applied as well. The PVD coating has a high degree of resistance to wear and scratches, while about 1 μm of gilding is erased per year, depending on clothing, etc. The PVD coating technology makes it possible to get very thin (from 1 to 3 μm, sometimes up to 5 μm) coating layers without any impurities. IPG (IonPlating Gold) is a method of ion deposition of gold with a substrate (an intermediate hypoallergenic layer). Today this kind of gilding is the most resistant to wear (IPG coating is 2-3 times more durable than a PVD coating of the same thickness). The thickness of the gilding is 750 °: 1-2 μm.

Retrograde - means ‘moving backwards’. It is a hand that moves along an arc, and as soon as it reaches the end of the scale, moves back to the zero mark.

Skeleton - a watch with a transparent dial and a back cover of the case, so you can observe the operation of a complicated mechanism.

Split-chronograph - a watch with a stopwatch, which has the function of an intermediate finish.

The tourbillon - one of the most difficult watch functions, together with a minute repeater, time equalizer and eternal calendar. It is a mechanism that compensates the influence of the Earth's gravity for the accuracy movement of the watch. It is an anchor mechanism placed inside a mobile platform with a balance in the center, that makes a complete turn around its own axis in one minute. It was invented in 1795 by Abraham Luis Breguet (A.L.Breguet).

The lug – a part of the watch case, where a bracelet or strap is attached.

Chronograph - a watch with two independent measuring systems: one shows the current time, the other measures short periods of time. The counter registers seconds, minutes and hours and can be turned on or off at will. The central second hand of such watch is usually used as the second hand of a stopwatch.

Watch glass - usually a transparent plastic, mineral or sapphire crystal is used.