Glossary of Watch Terms

This page sets out a glossary of terms relating to watches, watch making and all things horological. If you think we're missing a useful description (or have a better definition for a term included below), please let us know by emailing feedback@time2.co.uk

A: Alarm, Analogue, Anti-Reflective Coating, ATM, Automatic, Automatic Calendar

Alarm

Alarms found within automatic watches, powered by a mechanical movement, have a quite different level of complexity to that found in a digital or indeed quartz watch. The alarm element within the movement will tend to have a distinct power source, with a separate subdial or alarm hand, along with a sound chamber within the case of the watch.

Analogue

An analogue watch uses hands or other moving elements within the dial to display the time, rather than displaying the time purely as a set of digits, whether by digital or mechanical means.

Some watches, such as those found in Gucci’s I-Gucci Collection, allow the wearer to chose between viewing digits or a digital analogue display.

Anti-Reflective Coating

An anti-reflective treatment usually applied to the inner surface of the watch crystal to reduce glare in direct sunlight and improve legibility. As the treatment is not scratch proof it tends only to be applied to the protected side of the crystal.

ATM

Standard unit of atmospheric pressure – used by watch makers to define the relative water resistance of their timepieces, with 1 ATM being equivalent to the water pressure experienced under 10m of water. Atmospheric pressure can also be expressed as Barometric pressure (BAR), equivalent to 0.986 ATM.

Automatic

Watches with an automatic movement rely purely on kinetic power to drive the intricate mechanical components found within and do not require a battery. Some styles include a window in the back of the case allowing a view of the mechanism within and the weighted balance wheel that draws its energy from the movement of the wearer.

Most automatic watches have a mechanism for storing the kinetic energy derived from the movement of the wearer – typically, an automatic will have up to 36 hours power reserve. If an automatic watch hasn’t been worn for a couple of days, it will generally need to be wound up by hand to get started again.

Automatic Calendar

Another term for Perpetual Calendar

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B: Battery Life, Bezel, Bracelet, Buckle

Battery Life

The minimum amount of time over which a battery will continue to provide the power to run a watch. Battery life begins when the factory initially installs the battery.

Bezel

The ring that encircles the face and holds the crystal. In some cases it contains an extra ring to beautify the case, or a rotating ring with a special function.

Bracelet

A metal strap that goes around the wrist consisting of links that can be removed to adjust the fit of a watch.

Buckle

Also known as Pin & Buckle

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C: Calibre, Case Back, Chronograph, Chronometer, Clasp, Complication, Crown, Crystal

Calibre

A descriptive term for the specific type of watch movement. Calibre was originally used to indicate the size of the movement, but has come to describe the type or shape of the movement, and is used to identify the origin and manufacturer of the mechanism.

Case

The watch case houses the internal moving parts of a watch.

Case Back

The reverse side of the watch case. It can be opened to access the watch movement, or battery for repair. Some automatic watches have a viewing window through which the watch mechanism can be viewed, known as an Open Case Back.

Chronograph

A watch with timekeeping or stopwatch functions. Analogue chronograph watches will tend to include additional hands or subdials in order to record seconds, minutes or hours independent of the main time display. With automatic watches a chronograph function is sometimes referred to as a ‘complication’ due to the additional complexity required in the mechanism of the movement.

Chronometer

Watches that have been tested for their time-keeping accuracy by a recognized testing organisation such as the Official Swiss Chronometer Testing Institute (COSC).

Clasp

A method for securing the two parts of a watch strap or bracelet. There are a variety of methods for securing a watch: a simple Pin & Buckle will secure the strap in much the same way as a belt buckle; a Deployment Clasp will fold away discretely behind the strap and when deployed, still connects the two parts of a strap (as the strap is never entirely released, they are sometimes also known as security clasps). Some ladies watches will employ a Jewellers or Jewellery clasp more frequently found on bracelets.

Complication

Complication is a watchmakers phrase for any function that adds additional complexity to the watch mechanism. Really only used in conjunction with descriptions of automatic or manual watches, there are two kinds of complication: standard complications include the display of an additional time zone, GMT, a power reserve, moon phase or full calendars. Attributes or functions such as tourbillions, split-second chronographs, perpetual calendars and minute repeaters, are described as Grande Complications.

Crown

The winding knob usually located at the 3 o’clock position. The crown is normally pulled out and rotated to adjust the time, date or day, and can also be used for winding up an automatic or manual watch.

Crystal

The transparent, protective covering over the face of the watch. It is held in place by the bezel, it may be made from plastic, glass or synthetic sapphire.

Also known as: glass, window

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D: Deployment Clasp, Dial, Dual Time

Deployment Clasp

A deployment clasp folds elegantly behind the strap so that it remains unseen. Typical examples will be made of 3 slender steel sections and will be deployed by either a single or double mechanism that allows the clasp to open out and release the strap.

Also known as: triple-folding clasp, push-button clasp, deployant clasp

Dial

The face of the watch which displays the time.

Divers’ Watch

Dual Time

A multifunction watch that measures current local time as well as at least one other time zone. The additional time zone will typically be displayed using an extra hand, a subdial or alternative digital display.

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E: Engine Turned, Electro Plating

Engine-turned

A decorative effect usually applied to the dial and displayed elements of the movement, that uses a revolving tool to score a pattern into a flat surface.

Also known as Machine-turned

Electro-plating

A plating process which uses electrolysis to bond a thin, durable layer of a desired material to a metallic base layer. Commonly employed to layer gold, silver or chrome over a steel base, the resultant plating is measured in microns (one thousandth of a millimetre). Similar processes such as PVD (Physical Vapour Deposition) are used to bond non-metallic materials such as carbon to a steel base in order to a create an extremely hardwearing surface layer.

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F: Flinqué, Fly-back, Fliplock Clasp

Flinqué

A term used to describe a decorative effect applied to watch dials where hand engraved or machine-turned decoration is covered with a layer of enamel.

Fly-back

An additional hand on a chronograph that moves with the seconds hand but can stop independently to measure a period and then “fly-back” to its starting position.

Fliplock Clasp

A folding safety clasp popularised by Rolex diver's watches. The folding elements of the clasp are locked down by a metal retainer.

 

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G: Gold Plate, GMT, Guilloché

Gold Plate

A thin gold covering, typically over stainless steel, measuring between 5 and 10 microns thick.

See also: Electro-plating, PVD

GMT

Greenwich Mean Time (GMT) refers to the solar time at the Meridian of Greenwich which used to be used as a basis for time throughout the world based on 24 hours.

Guilloché

An engraved wave-like pattern used on watch dials, that uses interlacing lines applied by hand or engine, for decorative effect. Additional metallic finishes may also be applied to the dial to further highlight this luxurious finish.

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H: Hands, Horology

Hands

Hands indicate the time on a watch. Watches tend to have three hands pointing to the hours, minutes and seconds.

Horology

The art of designing and making clocks, watches and other timepieces, or the study and measurement of time.

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I:

J: Jewels

Jewels

Synthetic sapphires or rubies used as bearings within automatic and manual watch mechanisms, used to reduce friction on key elements within the watch movement.

K:

L: Luminous

Luminous

Key elements within the dial, on the hands or index markers are coated with a luminous material such as Superluminova to enable a user to read the time in low light or night-time conditions ensuring that the watch dial is still legible without the need for a battery powered light source.

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M: Machine-turned, Manual, Moon Phase, Movement

Machine-turned

A decorative effect usually applied to the dial and displayed elements of the movement, that uses a revolving tool to score a pattern into a flat surface.

Also known as Engine-turned

Manual

A hand-wound mechanical watch that requires regular manual winding.

Moon Phase

A visual display of the waxing and waning moon as it proceeds through its lunar cycle.

Movement

A term used by horologists to describe an automatic or manual watch mechanism.

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N:

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O: Open Case Back

Open Case back

An additional sapphire or hardened glass crystal in the back of the watch showing the movement within.

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P: Perpetual Calendar, Pin & Buckle

Pavé

A setting of gemstones such that no metal is visible, especially when the stones are set very close together. Source: Wikipedia Example: Watches with pavé detailing.

Perpetual Calendar

A Grande Complication – perpetual calendars automatically account for the varying lengths of months and leap years to display the current calendar date without the need for manual adjustment.

Pin & Buckle

Like a belt buckle: a metal clasp through which the strap is passed and secured with a pin. Sometimes known as tang and buckle – a tang is a flattened pin.

Also known as: buckle, pin-buckle, ardillon buckle, tang & buckle

Plating

See: Electroplating

PVD

A plating process that uses Physical Vapour Deposition as a mechanism to bond metallic and non-metallic materials such as carbon to a steel base in order to a create an extremely hardwearing surface layer.

See also: Electoplating

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Q: Quartz

Quartz

A watch with a battery powered mechanism. The quartz drives the movement by a piezoelectric effect on a tiny quartz crystal to make it vibrate, which in turn drives the mechanism and allows the watch to keep extremely consistent time.

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R: Rotating Bezel

Rotating Bezel

A rotating ring that sits on top of the watch case, used for either decorative or practical effect. Rotating bezels will normally feature an additional index or set of markers and can be used for time-related calculations such as elapsed time in the case of conventional diving watches, or speed (distance over time) in the case of tachymetric watches. Some Breitling watches for instance, feature a slide rule built into the bezel, which was used by airline pilots for calculating measurements as significant as the amount of fuel remaining!

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S: Sapphire Crystal, Skeleton Case, Stainless Steel, Strap, Swiss Made, Subdial

Sapphire Crystal

A synthetic crystal which is very scratch resistant. Transparent sapphire is used for scratchproof watch glass.

Skeleton Case

A transparent front or back which allows inner parts of the watch to be seen.

Stainless Steel

A strong and durable metal containing chromium that makes it resistant to corrosion and discolouration; it can be highly polished which makes it aesthetically pleasing to the eye. Stainless steel can be used for case-backs and bracelets of watches.

Strap

A leather, plastic or fabric band that holds the watch on your wrist.

Swiss made

A watch must be of Swiss origin movement and must contain at least 50% Swiss parts. The watch must be cased in Switzerland and pass its final inspection in that country.

Subdial

A small dial found within the main face of a watch that can be used to display various information such as a seconds counter.

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T: Tachymeter, Tide Graph, Titanium, Tourbillon

Tachymeter

A measuring system to calculate speed, or average speed over a known distance.

See also: Rotating Bezel

Tide Graph

Tides are the ides rise and fall of the water of oceans, seas, bays etc. The tide graph indicates tidal movement based on the Moon's transit over the meridian and the lunitidal interval (the difference between moon up and the high tide immediately following moon up).

Titanium

Some watches are comprised of Titanium, an elemental metal often referred to as “space age metal”. It is very strong and lightweight making it great for watches. Titanium is also corrosion resistant.

Tourbillion

A regulating device which cancels out the variations in running regularity caused by Earth’s gravity of vertical positions (shifts of weight).

Trip-Tick^® Construction

A Bremont construction technique used for all of their watch cases consisting of three parts:

• the hardened steel bezel element containing the sapphire crystal.
• the central body section consisting of a PVD-treated middle barrel or titanium.
• the sapphire crystal back.

For both durability and aesthetics, the separate middle section allows our case designers to use differing metals, e.g. titanium, to alter the watch’s weight, while PVD allows Bremont to employ contrasting colours to distinguish between the various models.

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V:

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W: Water Resistant, Waterproof

Water Resistant or Waterproof

While no watch can be described as 100% waterproof, there are a number of build features that can ensure a very high degree of water resistance under differing levels of water pressure. Screw-down backs, screw-in crowns, thick steel one-piece cases, synthetic sealants etc. are used to provide a high degree of water resistance. The water resistant level is usually displayed in ATM, BAR or metres on the case back or face of the watch, and provides an indication of water resistance in unmoving water - and this is the key point: watches are tested to withstand pressure in a static and controlled environment. Activity in the water, even the simple action of moving through the water, will increase water pressure on the watch and so the following guidelines should be referred to when judging water resistance:

3 ATM / 3 BARS / 30m:	Splash resistant and suitable for everyday use but NOT suitable for swimming, snorkeling, fishing and other water related activities. Should not be worn in a shower or bath.
5 ATM / 5 BARS / 50m:	Suitable for swimming and some surface water sports but should NOT be worn for snorkeling or diving.3-5 working days
10 ATM / 10 BARS / 100m:	Suitable for recreational surfing, swimming, snorkeling, sailing and water sports but NOT suitable for diving
20 ATM / 20 BARS /200m:	Suitable for professional marine activity and serious surface water sports.
30 ATM / 30 BARS / 300m:	Suitable for scuba diving. In addition professional diver's watches may include a gas release valve or oil filled mechanism.

Bear in mind that constant use and exposure to certain chemicals may over time erode the original water resistance of a watch - sun cream, heavily chlorinated water and certain colognes may damage the synthetic seals (and may also affect the watch's finish). For more information on watch water resistance see: http://en.wikipedia.org/wiki/Diving_watch#Water_resistance

 

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X:

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Y: Yacht Timer

Yacht Timer

A timer which sounds warning alerts during the countdown to a boat race.

Z:

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