Watch Definitions

Analogue is a term used to describe how the time on a watch is displayed, which can either be through a series of digits, e.g. '04:32' (digital) or hands moving clockwise around a traditional clock face (analogue).

Automatic Movement
An automatic, or self-winding, movement is a mechanical movement first marketed in the beginning decades of the 20th century. An automatic movement winds itself while worn on the wrist, eliminating the need for daily hand winding. However, if not worn for some time (this includes wearing the watch in bed when it is largely at rest), the watch will stop and require a manual winding, which should take place when the watch is off the wrist to avoid damage to the movement, crown, and stem. Although less accurate than a quartz watch, an automatic watch is an artistic and engineering masterpiece that provides its owner with the joy of being able to admire and wear the culmination of hundreds of years of craftsmanship and expertise on his/her wrist. For those wishing more technical information, the key components of the automatic movement are the crown, mainspring, gear train, escapement, balance wheel, dial train, jewels and rotor (see definitions of each for further information) and these components work together as follows:

1. Movement of the wrist turns the rotor, which winds the mainspring. This can also be achieved by turning the crown.

2. The gear train transfers the energy to the escapement.

3. The escapement meters out the energy into regulated parts.

4. The balance wheel uses this regulated energy to beat back and forth at a constant rate.

5. Every certain number of beats, the dial train transfers the energy to the hands of the watch, and so the hands advance.

Balance Wheel
The balance wheel is the heart of a mechanical watch's movement, receiving the energy to run from the escapement. The balance wheel beats, or oscillates, in a circular motion between five and ten times per second. A watchmaker can make the balance wheel oscillate faster or slower, which in turn makes the watch run faster or slower.

Base Metal
Any non-precious metal.

In a quartz watch, the battery is the power source of the watch, and so has the same role as the mainspring in a mechanical watch. Typically, the battery on a quartz watch will last between 12 and 24 months, but some lithium batteries can last as long as 10 years before needing to be replaced. It is essential to replace the battery as quickly as possible once it has died as there is a possibility of it leaking acid and damaging the movement.Bezel

A metal or ceramic ring that usually surrounds the watch dial or crystal, although some can be inside/under the crystal. Often bezels rotate and contain a scale for time or other measurements, whilst others remain stationary or fixed, do not have a scale and are purely decorative.A bidirectional bezel can rotate either clockwise or anticlockwise to perform a specialised function. A unidirectional rotating bezel is a bezel designed to only rotate anticlockwise and is used on a diver's watch to track elapsed time in minutes. The advantage of the unidirectional bezel when diving is that if the bezel is accidentally moved or knocked, it will indicate that more time has been spent underwater than really has been, therefore indicating that there is less oxygen time than there really is, which therefore is a safety feature.

A bracelet is a flexible metal watch strap or band made of movable links. These can be adjusted to fit the wearer, often through detachable links, and sometimes have special clasps that allow them to expand to fit over a wetsuit or jacket.

The most common type of buckle in the watch industry is the tang, pin or ardillon buckle which looks and functions very much like a traditional belt buckle. The tail end of the strap is threaded through the loop of the buckle, which is then held in place by the pin (or tang) poking through a hole and resting in a recess in the loop. They can only be used on straps and bands made of a flexible material such as leather, rubber, fabric etc.

The housing used to protect the movement. Usually made of base or precious metal, it can also be made of plastic, carbon composite, ceramic, rubber or other materials.

Case Back
The reverse side of a watch's dial designed to protect the movement but which can be removed when necessary to gain access to the inner workings of the movement. Case backs are generally made of stainless steel, though they may include a crystal to show off the workings inside, in which case they are often called "exhibition" or "open" case backs. Case backs may be simply snapped in place or screwed in with rubber gaskets to protect against the entry of water and dust. Case backs often include information about the watch, like hallmarks, major specifications, or a serial number.

A term used to differentiate different types of movements made by the same manufacturer.

The most common watch clasp is the deployant (from the French word déployant, which means to unfold, extend, or unfurl) or folding clasp. Other examples include the butterfly and jewellery clasps. The deployant (and butterfly) clasps are usually seen on bracelets or metal straps and they close by folding in on themselves, and then clasping. They allow a strap or bracelet to stay in one piece, by opening and fastening using a hinged plate with adjustable extenders. Deployantbuckles are particularly popular with divers or aviators, who may need to adjust the band to go over a wetsuit or jacket. The deployant clasp makes the watch bracelet/strap easier to put on and take off and in the case of leather straps, prevents the leather from getting worn or stretched out.

The wheel on the side of the watch, normally at the 3 o'clock position, used to set the time and, if there is one, the date. It can also be turned to wind the watch's mainspring, and so run the watch. Screw-in or screw-down crowns, or similar mechanisms, seal the watch to keep out water at extreme depths.

A clear cover, sometimes also called a glass, that protects the dial (or back in the case of an exhibition/open back case). It can be made of acrylic glass (a tough, flexible and transparent plastic which is easily scratched), mineral glass (more scratch-resistant) or sapphire (natural or synthetic) crystal. Most sapphire crystals are synthetic, made of crystalised aluminium oxide. They are the most expensive to produce and are considerably more scratch resistant to scratching (but not scratch proof) as the synthetic sapphire is almost as hard as diamond. For this reason, often a mineral glass is coated with sapphire to make it more scratch-resistant.

Also often referred to as the face, the dial displays the time and features numerals and markings as well as the hands. 

Dial Train
On mechanical watches, a series of gears that transmit the regulated, equally metered energy from the balance wheel to the hands of the watch, making them move.

Dive Watch
A dive watch is a water-resistant watch, but not all water-resistant watches are dive watches. True dive watches should meet a specific standard for diving like ISO 6425, which requires the watch to be water-resistant to at least 200 meters, feature a unidirectional rotating bezel and some form of illumination.

A feature on a quartz watch that causes the second hand to jump in four second intervals when the battery is nearly exhausted. The jumping occurs every 4 seconds so the watch continues to display the correct time. The end of life indicator operates for about a week after which time the watch will stop. The EOL, therefore, indicates when your quartz watch needs a new battery.

The escapement in a mechanical watch movement acts as a brake, taking the energy transmitted from the mainspring through the gear train and pushing it out, hence "escaping", in equal, regular parts.

A rubber, neoprene or plastic ring used to seal the gaps between the case and the case back, crystal and crown to prevent water or dust from entering the case and damaging the movement inside.

Gear Train
The gear train transmits the stored energy from a mechanical watch's mainspring to the escapement through a series of small gears.

See Crystal.

See Manual Movement.

Helium Release Valve
Also called a helium escape valve. A valve set in a dive watch to prevent it from being damaged by helium. Dive watches with water resistance ratings of over 300 m (1,000 ft) are often worn by mixed-gas divers, who breathe a mixture of helium, hydrogen, and oxygen when working at extreme depths.

In between dives and when returning to the surface, the divers sit in a compression chamber filled with the same gas mixture. Because helium molecules are so tiny, they can slip past the watch's gasket and into the case. When the divers leave the chamber and return to sea level pressure, this trapped gas could severely damage the watch, so the one-way helium release valve is used to bleed off the helium when the internal case pressure becomes too great.

Integrated Circuit
In a quartz watch, the integrated circuit 'carries' the electrical charge between the various parts of the movement.

The jewels most often used in mechanical watches are synthetic rubies. The rubies are set at points where there is high friction, like the centre of a gear that is constantly in motion. Used as bearings to reduce metal-to-metal friction and wear, they improve performance and accuracy. Rubies are used because they absorb heat well and are extremely hard.

Loops on a watch strap or band designed to keep the surplus end length of the strap in place after its been fastened.

Curved protrusions from the case of the watch used for attaching a strap or bracelet by means of spring-loaded pins.

Metal components inside a mechanical watch can become magnetised if exposed to strong magnetic fields, thus causing a severe loss of accuracy. Magnetic fields are created by electronic devices such as computers, microwave ovens, mobiles, clock radios, stereo speakers and even items such as handbag fasteners, and bed underlays can generate magnetic fields. These magnetic fields can be transferred to the watch’s movement if the watch is placed close enough to them, normally less than 5 cms. When this happens, it can cause the escapement of the watch to act very erratically or in rare cases, seize up. This causes an erratic rate and as a result, large discrepancies in the time display. If your watch loses or gain many seconds or minutes a day, a good way to test if your watch has been magnetised is to wave it slowly and closely under a compass. If the compass hand moves, as a result, your watch has indeed been magnetised. Fortunately, de-magnetising a watch is a relatively simple process and can be done in a few minutes by a qualified watchmaker without opening the case.

Mainspring is the power source of mechanical watches. It is a spiral torsion spring of metal ribbon, commonly spring steel, used to power mechanical watches. Winding the crown or, in the case of automatic movements, rotating the watch and so rotor, stores energy in the mainspring by twisting the spiral tighter. The force of the mainspring then turns the clock's wheels as it unwinds.

Manual Movement
A manual movement, frequently called a hand-wound movement, is the oldest type of watch movement made, dating back to the 16th century. Manual movements require daily winding in order to function.  This winding should take place when the watch is off the wrist to avoid damage to the movement, crown, and stem. Manual movements are the most traditional movements and are usually found in very conservative, expensive, and collectable watches.

Although less accurate than a quartz watch, a manual watch is an artistic and engineering masterpiece that provides its owner with the joy of being able to admire and wear the culmination of hundreds of years of craftsmanship and expertise on his/her wrist. 

Mechanical Movement
A mechanical watch can either be automatic or manual/hand-wound, as opposed to quartz which is battery powered. A mechanical movement can be identified by the way the second-hand sweeps smoothly and without interruption around the dial, as opposed to a quartz watch's second hand which jumps in discrete one-second intervals. Mechanical watches are an artistic and engineering masterpiece that provide their owners with the joy of being able to admire and wear the culmination of hundreds of years of craftsmanship and expertise on their wrist.  See Automatic and Manual Movement definitions for further information.

Milanese Mesh
Milanese mesh bracelets are known by the unique design of the meshwork, which can be traced back to the 13th century, when it was used as a special chain-mail worn under the armour of ancient warriors. It is named after the Italian city of Milan, where they were first created by hand and a speciality of the region for centuries. The design is characterised by a dense and tight mesh of stainless steel wire links, which make them especially smooth to the wrist.

Mineral Glass / Crystal
See Crystal.

The engine of the watch. In other words, the inner-working mechanism that enables the watch to operate, mark time and perform its various functions. A mechanism can be either mechanical (automatic or manual/hand-wound) or quartz (battery-powered). 

See Automatic, Manual and Quartz Movement definitions for further information.

NATO Strap
A nylon fabric strap with an extra keeper strap added to run behind the watch and prevent it from falling off if one of the lug springs should give way. It was designed to be easily set to a number of sizes, including over clothing. It was originally developed by the British Ministry of Defence in 1973 and got its name from a shortening of the term "NATO Stocking Number."

As with all nylon straps, NATO straps are easy to clean and when wet, dry quickly, making them ideal for swimming. They are extremely tough, and as they are relatively inexpensive and available in many different colours and designs, they are extremely versatile and fashionable, providing a watch with many different looks.

Power Reserve
Mainly pertaining to mechanical watches, the power reserve is essentially the time the watch will run with a fully charged power supply. The normal power reserve for a mechanical watch, automatic or manual, is between 42 and 48 hours. Quartz movements normally have battery life from 18 months to 10 years depending on the case size, type of battery, watch functions running off the battery etc.

Precious Metal
Precious metals are rare, naturally occurring metallic chemical element of high economic value. They are usually ductile and have a high lustre. There are eight metals deemed to be precious: silver, gold, and the six metals of the platinum family (platinum, palladium, rhodium, ruthenium, iridium, and osmium).

PVD stands for Physical Vapor Deposition and is a chemical process where a thin layer of titanium nitride, an extremely dense and exceptionally hard metal compound, is infused deep into the base metal's crystalline structure. The coating takes place in a vacuum and provides the watch with efficient, long-lasting protection against accidental scratches, scrapes and blemishes. PVD is nearly as hard as sapphire, itself second only to diamond in hardness. The PVD process is safe, clean and environmentally friendly.

Quartz Crystal
The quartz crystal performs the same function as the balance wheel on a mechanical watch. The integrated circuit applies electricity from the battery to the quartz crystal in a constant stream. Quartz vibrates when electricity is applied to it and also generates a voltage when it vibrates.

Quartz Movement/Watch
A quartz watch is a battery-powered watch and so does not need or rely on winding or movement like a mechanical watch. A quartz watch can be recognised by the movement of its second hand, which jumps in discrete one-second intervals. Quartz watches are considerably more accurate, more reliable and cheaper than their mechanical counterparts. As opposed to a mechanical watch, the time on a quartz watch never needs to be reset as long as the battery still has a charge. 

For those wishing more technical information, the key components of a quartz movement consist of a battery, integrated circuit, quartz crystal, stepping motor and dial train (see definitions of each for further information) and these components work together as follows:

1. Electricity is carried from the battery to the quartz crystal via an integrated circuit.
2. The electricity makes the quartz crystal vibrate at a rate of 32,768 per second.
3. These electrical pulses are sent via the integrated circuit to the stepping motor.
4. The stepping motor sends every 32,768th electrical pulse to the dial train.
5. The dial train advances the hands on the watch.

Quick Release Strap
Straps/bands and bracelets can be attached to the watch case via built-in, quick release pins. These pins are tiny steel bars with a sliding protrusion, which can be pulled back by hand, which in turn pulls the spring pin ends out of the lugs. This can be done easily and gives the watch owner the ability to change the look and feel of the watch in just a few seconds without the use of any special tools.

In automatic watches, a rotor is a half circle-shaped metal weight attached to the movement that can swing freely in 360 degrees as the wrist moves. The rotor is connected by a series of gears to the mainspring and as it turns, it winds the mainspring, giving the watch energy. The rotor is equipped with a clutch that will disengage it from winding when the mainspring is fully wound.

Sapphire Glass / Crystal
See Crystal.

Stainless Steel
An extremely durable metal alloy (chromium is a main ingredient) that is immune to rust, discolouration, and corrosion. Stainless steel can be highly polished, thus resembling a precious metal and this bright shine does not discolour or wear off. Because of these features, it is often used for cases, case backs and bracelets. There are numerous grades of stainless steel available, but most watches are made of 316L, often called surgical-grade, which is resistant to chemicals and chlorides (like salt) and is hypoallergenic (unlikely to cause allergic skin reactions etc.).

Screw Back
See Case Back.

Stepping Motor
On a quartz movement, the stepping motor transforms the electrical impulses into mechanical power.

A band or strip of a flexible material, such as leather, rubber, silicone nylon or fabric that fastens and secures the watch case to the wearer's wrist.

Super-LumiNova is a brand name of a luminous material made by Luminova AG in Switzerland. It consists of a material known as strontium aluminate combined with a non-toxic and non-radioactive chemical element called Europium. It is used on watch hands, markers etc. and essentially operates like a light battery - after sufficient activation by sunlight or artificial light, they glow in the dark for hours, enabling the wearer to see the time in low light conditions like a cinema or theatre. Larger markings like those on a diver' swatch are visible for the whole night. This activation and subsequent light emission process can be repeated again and again without ever suffering from discolouration or ageing.

Swiss Made  
'Swiss Made' is a label created by the Swiss government to track and protect those watches which have the right to be marketed as made in Switzerland. The reason for this is that "Swiss Made" watches are made to the highest quality standards and involve craftsmanship and know-how gained over 300 years.

To be labelled "Swiss Made", the watch must conform to the following requirements:

1. The movement is Swiss, meaning:• it has been assembled in Switzerland.• it has been inspected by the manufacturer in Switzerland.• at least 60% of the manufacturing costs are generated in Switzerland.• at least 50% of the value of all the constituent parts, but excluding the cost of assembly, is of Swiss manufacture.2. The movement has been encased in Switzerland.3. Final inspection by the manufacturer took place in Switzerland.4. At least 60% of the manufacturing costs are generated in Switzerland.

An illegal and misused term as no watch is fully 100% waterproof.

An official designation for a watch case's ability to withstand water pressure as measured in metres (M), feet (FT), or atmospheres (ATM). It is important to note that this is a measure of pressure, not depth, and so a 5 ATM watch can withstand pressures equivalent to about 50 M (or 165 FT) underwater, but that does not mean the watch can be used diving to a depth of 50 metres. A brief guide to what can and cannot be done at which levels of water resistance are as follows:

• 5 ATM/50M/165FT: Suitable for shallow-water activities like swimming in a pool or ocean. It should not be worn when taking a shower/bath or diving into the water as the water is likely to hit the watch case at a pressure greater than 5ATM.

• 10 ATM, 100 M, 330 FT. Suitable for swimming, snorkelling but not suitable for high board diving or scuba-diving.

• 50 ATM, 500 M, 1,650 FT. Suitable for all high impact water sports, scuba diving and saturation diving.

It should be noted that the above does not apply to a watch with a leather strap as the leather will become deformed and discoloured if immersed in water. It should also be noted that if the crown is pulled out for any reason when the watch is exposed to water, the water will enter the mechanism and case, most likely causing irreparable damage. Lastly, if swimming in salt waters, the watch will need to be carefully cleaned afterwards in order to avoid salt deposits.