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GLOSSARY OF WATCH WORLD TERMS

The more you know about watches, the better equipped you

will be to compare and understand watch types and components.

Here is a simple and useful glossary of terms common to the

world of fine watches. If we have left something out, please

send email or make comments in the Guest Book.

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ANALOG WATCH Tells time using two hands and 12 or

24 hour baton markers, Arabic numbers, or Roman numerals

(or sometimes no hour markers at all as in the popular

Movado Museum watch).

ANTI-REFLECTIVE This term refers to the coating on the

crystal of the watch that is applied to cut glare, important for

pilots and often a feature of watches designed to appeal to

pilots such as Breitling, Chase-Durer, Poljot.

AUTOMATIC WATCH Self-winding. A mechanical watch that does not require manual winding. Wrist movements while wearing the watch move the rotor and wind the spring that powers the timepiece. When off the wrist, watches with automatic movements stop after 48-72 hours or may run up to 8-10 days on some high-end brands. Some automatic watches also feature a power reserve (see POWER RESERVE) complication. The French word perpetuelle is used to describe an automatic movement.

AUTOQUARTZ  Hybrid of automatic and quartz movements.

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BEZEL The ring of stainless steel, titanium, brass, or 18K gold that holds the watch crystal in place, usually seen on sports style watches and scuba diver's models such as Rolex Submariner, Omega Seamaster, and many others. Rotating bezels are used by divers to measure the time left in their air tanks. 

BRASS Alloy metal consiting of copper and zinc (65:35 ratio).

BUCKLE Fastener for leather band watches that may be a single or double deployment type. Usually called a clasp on metal watch bands, which also may be single or double deployment as well as locking clasp types.

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CALIBER or CALIBRE Synonymous with movement, or the engine of a watch. The French say guilloche. Manufacturers frequently give movements names to identify them, such as IWC Calibre 87.

CHRONOGRAPH Refers to the stopwatch functions of twp or three subdials on chronograph-style watches, such as the Rolex Daytona. This is a type of complication (see COMPLICATION) and should not be confused with a similar word, chronometer (see CHRONOMETRE).

CHRONOMETRE Officially certified chronometers are watches with high-grade movements that have been certified by Switzerland's COSC. (See COSC.)

COMPLICATIONS Measuring devices on watches indicating things other than hours and minutes of current time, such as day, date, month, moon phases, chronometer subdials, power reserve, rotating bezel, heart rate, tides, compass direction, water depth, barometric pressure, altitude, speed (tachymeter), air temperature, etc.

COSC Controle Officiel Suisse des Chronometres is the non-profit Swiss agency that certifies watch movements for accuracy. For more details about the COSC, go to the SwissWatchWorld HOME page and click on the COSC navigation button.

CROWN The winding crown is used to wind mechanical watches that are not automatic movement, and on all types of watches is used to set the hours and minutes. Some complications, such as day and date, may be quick set at one crown posiiton. On divers' watches, a screw-down crown ensures water resistance. 

CRYSTAL The clear cover over the watch face, it may be made of mineral crystal, acrylic, Plexiglass, or sapphire (the last being the hardest and best material for scratch resistance). Styles of crystals include domed and bubble types. Rolex made the 2.5x magnifying crystal bubble over the date window of their Date Just and Day Date models a classic.

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DEPLOYMENT CLASP This is the mechanism for opening up the watch bacelet, usually having two (single deployment) or three (double deployment) parts made of stainless steel, titanium, or 18K gold.

DIGITAL WATCH Indicates curent time in a numeric readout via liquid crystal display or LCD which replaced the earlier LED light-emitting diode.

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ETA The name of a Swiss movement manufacturer that makes a majority of the movements found in high quality watches, including the popular ETA 2892-A2, ETA 2681, and ETA/Valjous 7750 (chronograph).

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FLYBACK The movement of the hand of a chronograph subdial that returns to zero when a chronograph button is depressed.

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GMT Greenwhich Mean Time established by an international conference in 1884 that set the Prime Meridian running through the Royal Observatory in Greenwich, outside London, as 0 degree longitude. GMT watches show Greenwich Mean Time in a window or with a fourth hand and have 24 hour time indicators.

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HALLMARK Stamped marking on metal case indicating gold content, usually 18K in finest European watches and jewelry.

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INCABLOC This is a trade name for a shock-absorbing device used to protect the mechanical parts of a watch movement.

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JEWELS Usually synthetic rubies, jewels are used as bearings for parts of watch movements that are subject to wear. Basic hand-wound mechanical watches usually have 17 jewels, while automatics often have 25 to 31 jewels (and up to 57 as in the Audemars Piguet Dynamograph).

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LINK PINS AND SCREWS

LUGS Protrusions from the watch case from which the bracelet or watch strap is fitted.

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MECHANICAL WATCH  A watch that is either wound by hand or powered automatically by rotor and wrist movements, as opposed to quartz movements, which are powered by an oscillating crystal that draws power from a battery.

MOVEMENT The engine of the watch, whether mechanical or quartz. Often referred to as calibre by watch manufacturers.

MULTIFUNCTION WATCH  A watch with many complications, usually including day, date, alternate time zones, moon phases, power reserve, tachymeter, etc.

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O-RINGS  These are rubber or plastic seals to protect the watch movement from water and dust intrusion, especially important in water resistant timepieces.

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PERPETUAL CALENDAR

POWER RESERVE DISPLAY A complication on the watch face that shows the number of hours an automatic watch movement will remain running after being fully wound, usually 48 hours but much longer on some models, such as the .

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QUARTZ MOVEMENT Highly accurate watch engine powered by an oscillating crystal that runs on a small battery. Autoquartz is a hybrid.

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REFERENCE NUMBER Watch case number.

ROTOR The oscillating mass that winds automatic movements, which are powered by normal wrist and arm movements. It is the largest moving part seen through watches with back side crystal displays.

RUBY Synthetic rubies, used on movement parts subject to wear. (See JEWELS.)

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SAPPHIRE The hardest and most scratch resistant material used in watch crystals. It is about 40 times more scratch resistant than mineral crystal (glass).

SCREW-DOWN CROWN  The winder mechanism on the side of the watch (usually at 3 o'clock) that is screwed down to ensure water and dust protection for the movement, especially in diver-style watches. Many chronographs, such as the Rolex Daytona, have three screw-down crowns (two for sub-dial functions).

SELF-WINDING Another term to describe automatic watches.

SKELETON WATCH Timepieces with a see-through glass or sapphire back, or a face dial that reveals the watch movement either entirely or partially through a smaller port.

SUBDIAL Also known as a register, the subdial(s) indicate seconds on watches with no sweeping second hand, or function as stopwatch timers, day-date indicators, day-night or moon phase displays.

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TACHYMETER  A scale used to measure average speed over a distance, usually with markings on the watch bezel, popular with automobile racers and airplane pilots.

TONNEAU Barrel shaped. Usualy refers to the shape of the watch case.

TOURBILLION  A movement complication that allows the engine of a watch to rotate on its own axis and cancel out irregularities that cause inaccuracies.

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WATCH CRYSTAL The clear cover over the front (and sometimes the back) or the watch. It can be made of mineral crystal (glass), plastic, acrylic, or sapphire. Genuine sapphire is the most desirable material to use since it is many times harder and more scratch resistant than mineral crystal or glass. But even some of the most expensive watches in the world (such as Rolex) now use synthetic sapphire.

WATER RESISTANCE Different degrees of resistance to water pressure are indicated with notations such as 30 meters or 1000 meters, corresponding to depths at which movements were tested. WR of 200 meters is the minimum standard for diver's watches.