Watch Terminology/Glossary

Accuracy. Different watches and watch movements are accurate to different degrees. Generally quartz movements are more accurate than automatic/mechanical movements due to the complexity of the mechanical movement. Gravity, shock, magnetism, etc., can all effect the accuracy of your mechanical watch. In automatic movements 10-20 seconds plus or minus per day is not considered unusual.

Analogue Digital. A watch that has both a window digital display and the hands of a conventional watch.

The regulating mechanism of the watch, which vibrates on a hairspring. Lengthening or shortening the balance-spring makes the balance-wheel go faster or slower to advance or retard the watch timing.

Bezel. The bezel is a moveable ring on the top of a watch. The bezel is used for timing and can be moved either bi-directional (two way) or uni-directional (one way) on a ratchet system.

A rounded semi-precious stone or synthetic material, usually fitted onto the crown for ornamental purposes.

Caliber . The caliber of a watch usually describes the size and configuration of the movement.

Case. The case is the housing of the watch. Usually made from high grade stainless steel,  the case may come with an Exhibition Back, which is a glass hatch to show the movement.

Ceramic. Ceramic tiles are used as a protective shield for spacecraft re-entering the earth's atmosphere, thus it is a very durable and scratch resistant substance. Ceramic is polished with diamond dust to create a highly polished finish. Because ceramic can be injection molded, pieces can be contoured and shaped in many ways. It has a ultra smooth surface and can be produced in a wide range of colours.

Chronograph. Chronograph watches have different dials on the watch face that measure intervals of time, these may be seconds, minutes or hours elapsed. The dials are started or stopped via pushers on the side of the watch case.

Chronometer. Only watches that have passed the very rigorous accuracy tests of the Swiss Official Chronometer Control (COSC) are deemed chronometers. These watches are very accurate and are usually more expensive as a result.

Complication. A watch may have other dials on the face, possibly date, month, 24 hours or moonphase. These watches are called complications.

Crown. The crown has different uses for different watches. On a manual wound watch it is used to wind up the watch, on an automatic watch it can be used to quickstart the watch. On all watches, including quartz, it is used to adjust the time and also usually the date. The crown may be Screwed Down, which screws the crown into place for added water resistance and protection.

The dial is the watch face. Numerals, indices, or surface design can be applied, others may be printed on the dial.

Divers Watches. Divers watches are designed and manufactured specifically for divers who depend on the reliability of their watch under water. Divers watches must meet the vigorous standards regarding water and pressure resistance, legibility, setting function (rotating elapsed time bezel), should be antimagnetic, antishock, have rust resistance, easy to use, the ability to withstand sudden temperature changes, etc. Rotating bezels are essential on divers watches, which will only rotate anticlockwise, which means that if the case or bezel are moved the watch will not show an extended diving time. For accurate setting, the bezel should have a one minute interval click on a ratchet system. On many divers watches inscribed on the case back is the battery replacement date to prevent the watch from stopping during a dive. Straps should feature extra large buckles for easy fastening and longer length straps or steel bracelets to allow the watch to be worn over a diving suit. The bezel is usually set higher than the surface of the crystal lens to help protect it  from damage. Also larger luminous hands and markers are used for easy and clear readability under water. Usually rubber straps or steel bracelets are used for durability.

Face. The face is the visible area of the watch where the dial is contained. Most watch faces are printed or applied with Arabic or Roman numerals. Traditionally IIII, rather than IV, is used to indicate the 4 o'clock position.

Flyback Hand. The flyback hand on a chronograph watch is used to determine lap or finishing times, as in a stopwatch. To operate, the flyback and the regular second hand are set in motion, then to record a lap or finishing time, the flyback hand can be stopped. After taking the results, the button is pushed and the flyback hand will then catch up to the other second hand.

Glass/Lenses/Crystal. Watches basically use two types of glass lenses. Sapphire Crystal glass is extremely hard and virtually scratchproof, Hardened Mineral glass is also very hard, slightly below the scratchproof properties of sapphire glass.

Guilloche. Guilloche is a style of engraving that is popular on some watch dials, usually intricate lines that are interwoven to create a fine surface texture.

Hands. The hands are the pointing device of the watch. There are numerous types of hands, some of the most popular are;
Baton Hands, a narrow hand sometimes referred to as a stick hand; Dauphine Hands, a wide, tapered hand with a facet at the center running the length of the hand; Luminous Hands are hands which are filled with a luminous material for low light readability. Skeleton Hands are cut out hands showing only the frame.

Helium Escape Valve. A helium escape valve is used in some divers watches, usually found at 10 o'clock on the watch case. If a diver is underwater for a long period of time, upon resurfacing the diver will open the escape valve to release the pressure built up in the watch. It is possible that without an escape valve the watch could damage or even explode. This is not a feature that is used very often, as the wearer would have to be under water for a long period of time.

Jewels. Automatic or manual winding watches are often quoted as having a jeweled movement. Jewels, normally synthetic rubies, are used in movements to reduce friction. Because they can be made very smooth they allow metal parts to slide easily. Secondly, because jewels are extremely hard they wear very slowly, allowing the movement to last as long as possible.

Lugs. The lugs are extensions on either side of the case where the bracelet or strap is attached.

Luminous. Most watches have luminous hands and possibly markings on the dial. This means that the hands or indices are coated with a luminous substance, usually Tritium or Super-luminova, which allows the wearer to see the time in the dark or low light.

Moon Phase. Some watches have a dial on the watch face that keeps track of the phases of the moon. The moon rotates once around the earth every 29 days, 12 hours, and 44 minutes. Once set, the moon phase indicator accurately displays the phase of the moon.

Movement: The movement is the mechanism that powers the watch (see below).

1.Automatic Movements. Automatic movements are self-winding by the power of a rotor that winds a mainspring. The movement of the wearers wrist powers the watch, therefore an automatic watch requires no manual winding or battery to keep it working. However most automatic watches have a power reserve, usually about 30 hours, which means if the watch is unworn for longer than the power reserve it will stop.
2.Hand-winding Movements. Hand wound movements require manual winding of the crown by the owner regularly to keep the mainspring wound, otherwise the watch will stop.
3.Quartz Movements. Quartz movements use a battery to keep the watch working. These require replacing every few years normally. Quartz watches therefore keep running even when not worn for long periods.

Oscillation . The oscillation is the travel of the balance wheel from one extreme to the other and back again.

Perpetual Calendar.  This is a variety of calendar that can automatically adjust for months of different lengths and indicates 29th of  February in each leap year. Therefore a watch with a perpetual calendar requires far less adjustment.

Power Reserve. Some watches have a power reserve gauge on the dial to show how much power the watch has left.

Shock Absorbers. These are spring devices in balance wheel bearings that are used to divert shocks away from the very fragile pivot (usually 12/100mm diameter) to the sturdier parts of the balance staff. The springs allow the balance wheel to return to its original position after shocks, therefore maintaining accuracy in the watch.

Shock Resistance. Shock resistance can be specified on a watch case, which means the watch can withstand normal wear and tear, even during strenuous sport activities. All watches offer some shock resistance to the wearer.

Split Seconds. This is a second chronograph feature that runs concurrently with the first but can be stopped independently to record an intermediate time. It then catches up to run with the first hand again.

Stainless Steel. Most watch cases are constructed from stainless steel. This means that the case will not easily corrode. 316L stainless steel is a higher grade steel with an increased resistance to saltwater corrosion and overall increased toughness at all temperatures.

Strap/Bracelet. Watches usually come fitted with either leather or rubber straps that close with a buckle or clasp, or a steel bracelet, that also secures with a clasp. Divers watches are usually fitted with steel bracelets or rubber straps to avoid corrosion.

Subdial. A subdial is a smaller dial on a watchface. This can show many features such as elapsed minutes or hours on a chronograph, or possibly the date.

Sweep Seconds Hand. This is a seconds hand which is mounted in the centre of the watch dial instead of in a subdial.

Tachymetre. The Tachymetre is found around the rim of many watches, a gauge to measure speed.

Tank Watch. A tank watch is a watch with a rectangular case, inspired by the tank tracks of World War I and originally created by Louis Cartier.

Tonneau. A tonneau is a watch that has a barrel shaped case with two convex sides.

Tourbillon. A tourbillon is a part in some mechanical watches that eliminates timekeeping errors caused by slight variations due to gravity shifts when a watch changes position during use. The round carriage of the tourbillon holds the mechanism that rotates the wheels, thus the hands of the watch, at a continuous rate of once per minute. Tourbillons are usually very expensive due to this feature.

Vibration. A vibration is a swing of the balance. Therefore a watch which vibrates at 18,000 times an hour beats five times every second.

Water Resistance. Always a point of discussion within the watch industry. No watch is completely waterproof. A watch that is just defined as "Water Resistant" is usually only splashproof. A watch that is gauged as water resistant to 30 metres can be immersed in water up to 30 metres deep. An Atmosphere is a unit of measurement, 1 atmosphere measures 10 metres, therefore a watch deemed water resistant to 50 atmospheres is equivalent to 500 metres water resistance. Divers watches should be resistant to 330 feet (10 ATM or 100 metres) minimum. Measurements of water resistance are as follows:

Water resistant. Splashproof,  but should not be worn while swimming or diving.
Water tested to 50 metres (165 feet). Suitable for swimming in shallow water.
Water tested to 100 metres (330 feet). Suitable for swimming and snorkeling.
Water tested to 150 metres (500 feet).  Suitable for snorkeling.
Water tested to 200 metres (660 feet). Suitable for skin diving.
Diver's to 150 metres. Meets ISO Standards and is suitable for scuba diving.
Diver's to 200 metres. Meets ISO Standards and is suitable for scuba diving.

World Timer. Worldtimer watches have a dial that indicates up to 24 time zones around the world, The time zones are usually found on the outer edge of the face or sometimes on the bezel or case. The time zones around the world are indicated by the major cities.