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https://www.govbergwatches.com/blog/glossary-of-watch-parts-and-terminology/
12 or 24 Hour RegisterThe register, also known as a recorder, is a sub-dial on the face of a chronograph that can record periods of time up to 12 or 24 hours.
30 Minute RegisterSimilar to the hour register, the 30 minute register is a sub-dial on a chronograph that records periods of time up to 30 minutes.
Anti-MagneticIs a watch that uses certain alloys in parts of the watch including the escape and balance wheel. This allows the watch to be unaffected by a magnetic field and not lose time. Simple items such as a TV, cell phone or stereo can cause enough magnetism to counteract the balance, preventing the watch to keep time accurately.
ApertureThe small window that is either carved or cut into the dial to display various indications, including the date.
ATM (Atmosphere)
A unit of pressure for the standard atmospheric pressure at sea level. One atmosphere is the pressure of 1kg/cm2 and corresponds to 10 meters of depth. An ATM is displayed as a value such as 5ATM.
Automatic Watch
Is a type of mechanical watch. It winds with the movement of the wearer’s wrist by a small weight rotating with the motion. Automatic watches can also be manually wound by turning the crown. Learn more about automatic movements.
Auxiliary Dial
An extra dial for information, also referred to as a subdial, different information is displayed depending on the complication. Watches can have as many as four auxiliary dials, typically found on chronographs, alarm watches or dual time zones but not restricted to these style watches.
Balance Spring
Also called the hairspring; the spring governing the balance wheel. It coils and recoils to swing the balance wheel to regulate time.
Balance Wheel
A device which regularizes the movement to regulate time equally in a watch or clock. This works the same way a pendulum works.
Balance Wheel
BandThe strap that wraps around your wrist to keep the watch in position. Typically referring to a leather or rubber band, often called a strap.
BarAnother unit of measurement relating to the pressure a watch can withstand. One bar is about equal to the atmospheric pressure at sea level and is approximately 10 meters.
Barrel
The drum-shaped container that houses the mainspring in a mechanical watch. The size of the barrel directly corresponds to how long the power reserve will hold. A double barrel will increase the power reserve.
Battery Reserve Indicator
The end-of-life indicator on a quartz watch. Typically the second hand will jump in two to four second intervals.
BeatRefers to the vibration or the tick of a watch; about 1/5 of a second. The sound is produced by the escape wheel striking the pallets.
Bevel
A filed, turned or obliquely ground surface made to avoid a sharp edge.
Bezel
The rim that surrounds the dial (face) and retains the crystal. Often made of precious metals, or unique materials. A bezel can be used to measure speed, distance or elapsed time.
Bi-Directional Rotating BezelThe type of bezel used to track elapsed time. They can be turned clockwise or anti-clockwise.
Bracelet
Is the metal version of a band or strap used to keep the watch in position on your wrist. Created using metal links that can be removed for sizing.
Bridge
Metal part in which at least one of the pivots of the moving parts of a watch usually turns. A bridge is strictly a bar with two supports. A bar is fixed to the bottom plate by steady-pins. Bars are generally named after the parts they support e.g. barrel-bar, center-wheel bar, etc.
Cabochon
Precious stone, polished but uncut. In French, the word is also used for an embossed ornament on a dial, and of a fancy gilt nail or stud as used by upholsterers. Typically found set in the crown of a watch.
Calendar
A complication showing the date and the month. It often shows the day of the week and the year depending on the complexity of the movement.
Caliber (Calibre)
The term identifying movements from their architecture, origin, reference and maker. It is part of the movement identifying the position and size of the wheel train.
Case
Container that protects the watch movement from dust, moisture and shocks, often referred to as the body of the watch. It gives the watch as attractive an appearance as possible, subject to fashion and the taste of the public and is created out of different materials and precious metals.
Caseback
The reverse side of the watch case, laying flat on your wrist. Some watches feature an exhibition caseback that is transparent allowing you to see the movement. Casebacks typically carry some engraving noting the name, water resistance and other details.
Chime
A bell like sound made when a clock strikes on the hour, half hour, quarter hour and minutes. The chime is similar to that found in a grandfather clock.
Chronograph
A chronograph is a watch that does not only indicate the time of the day in hours, minutes and seconds, but is also equipped with an additional mechanism – operated manually by push buttons –which makes possible to measure continuous or discontinuous intervals of time, from a fraction of a second to 12 hours.
Chronometer
A precision watch, finely set and tested in various positions and temperatures, for which an official certificate has been issued. The test is preformed by the official Swiss testing laboratory called the Controle Officiel Suisse des Chronometeres (COSC) and watches go through a rigorous 15 day test.
Cloisonne
Enamel set between strips of metal and baked onto the dial.
Cloisonne
Column Wheel
The upright, notched, rotating wheel in a chronograph that acts as a sliding link to operate the various levers that turn a chronograph on and off and return the chronograph hands to the zero position.
Complication
A multi-part mechanism providing an additional horological function, providing more information than just the time. Complicated functions include minute repeater, tourbillon, perpetual calendar, split second chronograph and others.
Complications
Cosmograph
Invented by Rolex, it is similar to a chronograph except for the fact that the tachymeter is on the bezel rather than the outer rim of the dial.
Crown
Device with which to wind the watch. Can be a screw down version or pull-out. Crowns are also used to set the time and the calendar.
CrystalThe clear cover protecting the dial from dust and damage. A crystal is typically made of glass, acrylic, mineral or sapphire.
CyclopsA small magnified lens found on the crystal that is located above the date to make it easier to read.
Cyclops on Watch Crystal
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Elapsed Time Rotating BezelGraduated rotating bezel to keep track of periods of time. Elapsed time can be read off of the bezel rather than needing to subtract time if using a regular dial.
Enamel
Substance composed of siliceous sand to which oxides are added to give a very wide range of colors suitable for the decoration of metallic surfaces, especially gold, silver or copper. When fired, enamel adheres to the metal and acquires the consistency of glass.
Engine Turning
Engraving a watch case with a repetitive design by antique machines. This can be done on the dial, case, bezel or movements. Also referred to as “Guilloche”
Equation of Time
A complication showing true solar time in nature and mean solar time in man. There are only four days per year where the day is exactly 24-hours long. On every other day, the days are slightly shorter or longer depending on the position of the Earth.
Escape Wheel
The last wheel in a going train; works with the fork or lever and escapes one pulse at a time.
Escape Wheel
Escapement
Mechanism fitted between the train and the regulating organ of most timepieces. The purpose of the escapement is to maintain the oscillations of the regulating organ. The escapement is one of the most important parts of any watch.
Escapement
Exhibition Caseback
Also can be referred to as a skeleton caseback, this shows off the movement through a second crystal located on the back of the case.
Fly-Back Hand
In a split-seconds chronograph, a second center seconds hand that can move while remaining superimposed on the first hand, but can be stopped and brought back to zero together with the first hand as it moves. It can also be stopped and brought back to zero together with the first hand and is useful to aviators
Frequency
The number of vibrations, oscillations, per second, in hertz (Hz) that a watch’s regulating organ makes per unit of time.
Fusee
A spiral grooved, truncated cone used in some watches to equalize the power of the mainspring.
Fusee Chain
Gasket
A small ring to create an air-tight seal around the caseback, crystal and crown. It protects against water during normal wear. Gaskets are rubber and should be checked every few years to maintain water resistance.
Gear Train
A system of gears the transfers power from the mainspring to the escapement.
Geneva Seal
The quality seal awarded by an independent bureau in Geneva. Companies submit movements to this bureau for testing. They are tested against 12 different criteria related to the quality of the movement, including the finishing and materials. Movements must also be manufactured in Geneva. The Geneva coat of arms is stamped onto the movement.
GMT TimeAlso known as Greenwich Mean Time, it is the international standard of time that the world is set to. Every time zone is set against GMT. In watches, a GMT reference refers to the ability to show dual time zones with a second hour hand, primarily found in a 24-hour mode to determine day from night.
Gold Plated
Also known as gilt, it is a thin layer of gold fused onto another metal to appear gold.
Grande Sonnerie
A watch or clock that strikes the hour, quarter hours and minutes when the wearer pushes the button; a Petite Sonnerie strikes at the hour only.
Guilloche
Extremely varied pattern of crossing or interlaced lines, giving a decorative effect. It is an especially complicated mechanical engraving technique.
Guilloche
Return To Top
IndexAn hour indicator on an analog watch. Used in place or alongside numerals.
Jewel
A bearing made of a ruby or other type jewel or synthetic gemstone; the four types of jewels include: cap jewel, hole jewel, roller jewel or ruby pin, pallet jewel or stone. Used to reduce friction in the movement of mechanical watches.
Jumping Hour
Hour numerals that appear through an aperture in a dial rather than a moving hand.
Karat (k)The Karat, like all jewelry, is an indication showing the purity of metal, such as gold, representing the purity. In gold, 24k is pure, while 18k is 18 parts pure and 6 parts other metal.
Lacquer
A vegetable product, the resin of certain trees found in the Far East (China, Japan), which gives a fine black or red color. The term may also be used to denote articles made of several layers of hardened lacquer.
Lever EscapementPart of the movement that divides into two pallets that lock and unlock the escape wheel teeth.
Limited EditionA watch manufactured in a specific amount, typically numbered and available in limited quantities. These watches are highly sought after.
Liquid Crystal Display
Also known as LCD, it is another term for digital watches, showing an arabic numeral display. The liquid is encased between two clear plates and activated by electronic impulses.
Lug
Curved attachment of the watch case to attach the bracelet, strap or band.
LuminousLuminous (lume) markers and hands are made by applying glow in the dark coating to the indicator. This allows them to illuminate automatically in a darkened environment.
Mainspring
A flat spring coiled or wound to supply power to the watch.
Mainspring
Maltese Cross
The part of the watch that prevents the barrel from being over wound, not found in all models.
Manual Winding
A watch wound daily by winding the crown to tighten the spring. Most manual wind watches hold time for 36-48 hours before needing to be rewound. Learn more about manual wind watches.
Marine Chronometer
An accurate timepiece typically found on a ship. These are used for determining the longitude. Found in a box that is mounted to keep in a horizontal position to maintain precision.
Mechanical Watch
Mechanical watches are the most traditional type of watch. They usually consist of about 120-180 individual parts. This is a watch that runs without any electrical source and can consist of manual wind watches or automatic watches.
Meter
The most common unit of measurement when referring to the water resistance of a watch. Relates to how deep a watch is able to go, testing is done in a controlled laboratory.
Mineral Glass
Far more scratch-resistant than synthetic glass. Hardness level 5.
Minute Repeater
A timepiece that can be made to strike the time in hours, quarters and minutes, by means of a push piece or slide.
Mono-Pusher ChronographA type of chronograph that is started using a single button rather than multiple.
Moon Phases
A complication that represents waxing and waning of the moon as it circles the earth. This complication is shown in a window on the watch dial.
Moonphase
Mother of Pearl
Interior shell that is thinly sliced and used as a watch dial. Most are found with a white luster but can be found in gray, blue, pink and salmon tones.
Movement
The fully functioning assembly of all the main timekeeping organs of a watch. Three main movements include mechanical, automatic and quartz.
Return To Top
Power Reserve
Running time in excess of the normal time (24 hours for ordinary watches) between two consecutive windings. In an ordinary watch, the power reserve usually provides for 10 to 16 hours running. Some watches feature a Power Reserve Indicator to alert the wearer of time remaining until the watch stops. Can also be referred to as the Reserve de Marche.
Power Reserve Indicator
Quartz Movement
Quartz watches are battery powered. They can either have hands, like the more traditional mechanical watch, or have a digital display. These watches are much more accurate than even the most expensive manual wind watches. Learn more about the quartz movement and the quartz revolution.
Return To Top
Tachymeter
A tachymeter (also known as tachometer) measures the speed at which the wearer has traveled over the measured distance found commonly on a chronograph. The wearer starts the chronograph when passing the starting point and stops it when passing the finish. The wearer can then read the speed in units per hour off the tachymeter scale.
Tang Buckle
One of the most common strap closures found. A traditional loop and pin that resembles a belt buckle.
Tank Watch
Designed by Cartier, it is a rectangular watch with bars along the sides the resemble the tracks of a tank used in World War I.
Telemeter
A telemeter determines the distance of an object from the observer by measuring how long it takes sound to travel that distance. Like a tachymeter, it consists of a stopwatch, or chronograph, and a special scale, usually on the outermost edge of the watch dial. One application of a telemeter would be determining the distance of a storm from its observer. The wearer starts the chronograph at the instant the flash of lighting is seen, then stops it when thunder is heard. A reading can then be taken to determine the distance of the storm from the observer in miles on the telemeter scale.
TonneauA barrel shaped case with two convex sides.
Totaliser / TotalizerA mechanism used to track elapsed time, typically found in a subdial.
Tourbillon
A device invented by A.L. Breguet in 1801 to eliminate errors of rate in the vertical positions. It consists of a mobile carriage or cage carrying all the parts of the escapement, with the balance in the center. It is designed to avoid any errors that may be caused by a change in the wearers wrist position. Tourbillons typically rotate one per minute.
Tourbillon
Uni-Directional Rotating Bezel
Typically found on divers’ watches. The bezel only rotates in a counterclockwise direction and is designed to prevent a diver from running out of air by over estimating remaining air supply.
Universal Time
Mean solar time for the Greenwich meridian, but counted from noon to noon.
Vibration
The movement of an oscillating part of the watch, limited by two extreme positions. Generally 5 or 6 vibrations per second, 18,000 or 21,600 per hour, but can also be a higher frequency with as many as seven or ten vibrations, 25,200 or 36,000 per hour. See also: Frequency.
Water-Resistant
The case, crown, push button and glass of a water-resistant watch are made in such a way that no dust or water can penetrate. Watches undergo in-house tests in a laboratory under controlled conditions. Learn more about water resistance markings.
Waterproof
A prohibited term used when describing the water resistance of a watch. No watch is 100% waterproof.
Winding StemAnother word used for the crown. A button found on the side of the case used to wind the mainspring.
World Time ComplicationA dial that contains up to 24 different time zones, found usually on the outer edge of a dial. The time zones are represented by using the names of major cities.
World Time
Yacht Timer
A countdown timer used to sound warning signals during a race, originally developed for the countdown to a boat race.
https://www.govbergwatches.com/blog/glossary-of-watch-parts-and-terminology/
12 or 24 Hour RegisterThe register, also known as a recorder, is a sub-dial on the face of a chronograph that can record periods of time up to 12 or 24 hours.
30 Minute RegisterSimilar to the hour register, the 30 minute register is a sub-dial on a chronograph that records periods of time up to 30 minutes.
Anti-MagneticIs a watch that uses certain alloys in parts of the watch including the escape and balance wheel. This allows the watch to be unaffected by a magnetic field and not lose time. Simple items such as a TV, cell phone or stereo can cause enough magnetism to counteract the balance, preventing the watch to keep time accurately.
ApertureThe small window that is either carved or cut into the dial to display various indications, including the date.
ATM (Atmosphere)
A unit of pressure for the standard atmospheric pressure at sea level. One atmosphere is the pressure of 1kg/cm2 and corresponds to 10 meters of depth. An ATM is displayed as a value such as 5ATM.
Automatic Watch
Is a type of mechanical watch. It winds with the movement of the wearer’s wrist by a small weight rotating with the motion. Automatic watches can also be manually wound by turning the crown. Learn more about automatic movements.
Auxiliary Dial
An extra dial for information, also referred to as a subdial, different information is displayed depending on the complication. Watches can have as many as four auxiliary dials, typically found on chronographs, alarm watches or dual time zones but not restricted to these style watches.
Balance Spring
Also called the hairspring; the spring governing the balance wheel. It coils and recoils to swing the balance wheel to regulate time.
Balance Wheel
A device which regularizes the movement to regulate time equally in a watch or clock. This works the same way a pendulum works.
Balance Wheel
BandThe strap that wraps around your wrist to keep the watch in position. Typically referring to a leather or rubber band, often called a strap.
BarAnother unit of measurement relating to the pressure a watch can withstand. One bar is about equal to the atmospheric pressure at sea level and is approximately 10 meters.
Barrel
The drum-shaped container that houses the mainspring in a mechanical watch. The size of the barrel directly corresponds to how long the power reserve will hold. A double barrel will increase the power reserve.
Battery Reserve Indicator
The end-of-life indicator on a quartz watch. Typically the second hand will jump in two to four second intervals.
BeatRefers to the vibration or the tick of a watch; about 1/5 of a second. The sound is produced by the escape wheel striking the pallets.
Bevel
A filed, turned or obliquely ground surface made to avoid a sharp edge.
Bezel
The rim that surrounds the dial (face) and retains the crystal. Often made of precious metals, or unique materials. A bezel can be used to measure speed, distance or elapsed time.
Bi-Directional Rotating BezelThe type of bezel used to track elapsed time. They can be turned clockwise or anti-clockwise.
Bracelet
Is the metal version of a band or strap used to keep the watch in position on your wrist. Created using metal links that can be removed for sizing.
Bridge
Metal part in which at least one of the pivots of the moving parts of a watch usually turns. A bridge is strictly a bar with two supports. A bar is fixed to the bottom plate by steady-pins. Bars are generally named after the parts they support e.g. barrel-bar, center-wheel bar, etc.
Cabochon
Precious stone, polished but uncut. In French, the word is also used for an embossed ornament on a dial, and of a fancy gilt nail or stud as used by upholsterers. Typically found set in the crown of a watch.
Calendar
A complication showing the date and the month. It often shows the day of the week and the year depending on the complexity of the movement.
Caliber (Calibre)
The term identifying movements from their architecture, origin, reference and maker. It is part of the movement identifying the position and size of the wheel train.
Case
Container that protects the watch movement from dust, moisture and shocks, often referred to as the body of the watch. It gives the watch as attractive an appearance as possible, subject to fashion and the taste of the public and is created out of different materials and precious metals.
Caseback
The reverse side of the watch case, laying flat on your wrist. Some watches feature an exhibition caseback that is transparent allowing you to see the movement. Casebacks typically carry some engraving noting the name, water resistance and other details.
Chime
A bell like sound made when a clock strikes on the hour, half hour, quarter hour and minutes. The chime is similar to that found in a grandfather clock.
Chronograph
A chronograph is a watch that does not only indicate the time of the day in hours, minutes and seconds, but is also equipped with an additional mechanism – operated manually by push buttons –which makes possible to measure continuous or discontinuous intervals of time, from a fraction of a second to 12 hours.
Chronometer
A precision watch, finely set and tested in various positions and temperatures, for which an official certificate has been issued. The test is preformed by the official Swiss testing laboratory called the Controle Officiel Suisse des Chronometeres (COSC) and watches go through a rigorous 15 day test.
Cloisonne
Enamel set between strips of metal and baked onto the dial.
Cloisonne
Column Wheel
The upright, notched, rotating wheel in a chronograph that acts as a sliding link to operate the various levers that turn a chronograph on and off and return the chronograph hands to the zero position.
Complication
A multi-part mechanism providing an additional horological function, providing more information than just the time. Complicated functions include minute repeater, tourbillon, perpetual calendar, split second chronograph and others.
Complications
Cosmograph
Invented by Rolex, it is similar to a chronograph except for the fact that the tachymeter is on the bezel rather than the outer rim of the dial.
Crown
Device with which to wind the watch. Can be a screw down version or pull-out. Crowns are also used to set the time and the calendar.
CrystalThe clear cover protecting the dial from dust and damage. A crystal is typically made of glass, acrylic, mineral or sapphire.
CyclopsA small magnified lens found on the crystal that is located above the date to make it easier to read.
Cyclops on Watch Crystal
Return To Top
Elapsed Time Rotating BezelGraduated rotating bezel to keep track of periods of time. Elapsed time can be read off of the bezel rather than needing to subtract time if using a regular dial.
Enamel
Substance composed of siliceous sand to which oxides are added to give a very wide range of colors suitable for the decoration of metallic surfaces, especially gold, silver or copper. When fired, enamel adheres to the metal and acquires the consistency of glass.
Engine Turning
Engraving a watch case with a repetitive design by antique machines. This can be done on the dial, case, bezel or movements. Also referred to as “Guilloche”
Equation of Time
A complication showing true solar time in nature and mean solar time in man. There are only four days per year where the day is exactly 24-hours long. On every other day, the days are slightly shorter or longer depending on the position of the Earth.
Escape Wheel
The last wheel in a going train; works with the fork or lever and escapes one pulse at a time.
Escape Wheel
Escapement
Mechanism fitted between the train and the regulating organ of most timepieces. The purpose of the escapement is to maintain the oscillations of the regulating organ. The escapement is one of the most important parts of any watch.
Escapement
Exhibition Caseback
Also can be referred to as a skeleton caseback, this shows off the movement through a second crystal located on the back of the case.
Fly-Back Hand
In a split-seconds chronograph, a second center seconds hand that can move while remaining superimposed on the first hand, but can be stopped and brought back to zero together with the first hand as it moves. It can also be stopped and brought back to zero together with the first hand and is useful to aviators
Frequency
The number of vibrations, oscillations, per second, in hertz (Hz) that a watch’s regulating organ makes per unit of time.
Fusee
A spiral grooved, truncated cone used in some watches to equalize the power of the mainspring.
Fusee Chain
Gasket
A small ring to create an air-tight seal around the caseback, crystal and crown. It protects against water during normal wear. Gaskets are rubber and should be checked every few years to maintain water resistance.
Gear Train
A system of gears the transfers power from the mainspring to the escapement.
Geneva Seal
The quality seal awarded by an independent bureau in Geneva. Companies submit movements to this bureau for testing. They are tested against 12 different criteria related to the quality of the movement, including the finishing and materials. Movements must also be manufactured in Geneva. The Geneva coat of arms is stamped onto the movement.
GMT TimeAlso known as Greenwich Mean Time, it is the international standard of time that the world is set to. Every time zone is set against GMT. In watches, a GMT reference refers to the ability to show dual time zones with a second hour hand, primarily found in a 24-hour mode to determine day from night.
Gold Plated
Also known as gilt, it is a thin layer of gold fused onto another metal to appear gold.
Grande Sonnerie
A watch or clock that strikes the hour, quarter hours and minutes when the wearer pushes the button; a Petite Sonnerie strikes at the hour only.
Guilloche
Extremely varied pattern of crossing or interlaced lines, giving a decorative effect. It is an especially complicated mechanical engraving technique.
Guilloche
Return To Top
IndexAn hour indicator on an analog watch. Used in place or alongside numerals.
Jewel
A bearing made of a ruby or other type jewel or synthetic gemstone; the four types of jewels include: cap jewel, hole jewel, roller jewel or ruby pin, pallet jewel or stone. Used to reduce friction in the movement of mechanical watches.
Jumping Hour
Hour numerals that appear through an aperture in a dial rather than a moving hand.
Karat (k)The Karat, like all jewelry, is an indication showing the purity of metal, such as gold, representing the purity. In gold, 24k is pure, while 18k is 18 parts pure and 6 parts other metal.
Lacquer
A vegetable product, the resin of certain trees found in the Far East (China, Japan), which gives a fine black or red color. The term may also be used to denote articles made of several layers of hardened lacquer.
Lever EscapementPart of the movement that divides into two pallets that lock and unlock the escape wheel teeth.
Limited EditionA watch manufactured in a specific amount, typically numbered and available in limited quantities. These watches are highly sought after.
Liquid Crystal Display
Also known as LCD, it is another term for digital watches, showing an arabic numeral display. The liquid is encased between two clear plates and activated by electronic impulses.
Lug
Curved attachment of the watch case to attach the bracelet, strap or band.
LuminousLuminous (lume) markers and hands are made by applying glow in the dark coating to the indicator. This allows them to illuminate automatically in a darkened environment.
Mainspring
A flat spring coiled or wound to supply power to the watch.
Mainspring
Maltese Cross
The part of the watch that prevents the barrel from being over wound, not found in all models.
Manual Winding
A watch wound daily by winding the crown to tighten the spring. Most manual wind watches hold time for 36-48 hours before needing to be rewound. Learn more about manual wind watches.
Marine Chronometer
An accurate timepiece typically found on a ship. These are used for determining the longitude. Found in a box that is mounted to keep in a horizontal position to maintain precision.
Mechanical Watch
Mechanical watches are the most traditional type of watch. They usually consist of about 120-180 individual parts. This is a watch that runs without any electrical source and can consist of manual wind watches or automatic watches.
Meter
The most common unit of measurement when referring to the water resistance of a watch. Relates to how deep a watch is able to go, testing is done in a controlled laboratory.
Mineral Glass
Far more scratch-resistant than synthetic glass. Hardness level 5.
Minute Repeater
A timepiece that can be made to strike the time in hours, quarters and minutes, by means of a push piece or slide.
Mono-Pusher ChronographA type of chronograph that is started using a single button rather than multiple.
Moon Phases
A complication that represents waxing and waning of the moon as it circles the earth. This complication is shown in a window on the watch dial.
Moonphase
Mother of Pearl
Interior shell that is thinly sliced and used as a watch dial. Most are found with a white luster but can be found in gray, blue, pink and salmon tones.
Movement
The fully functioning assembly of all the main timekeeping organs of a watch. Three main movements include mechanical, automatic and quartz.
Return To Top
Power Reserve
Running time in excess of the normal time (24 hours for ordinary watches) between two consecutive windings. In an ordinary watch, the power reserve usually provides for 10 to 16 hours running. Some watches feature a Power Reserve Indicator to alert the wearer of time remaining until the watch stops. Can also be referred to as the Reserve de Marche.
Power Reserve Indicator
Quartz Movement
Quartz watches are battery powered. They can either have hands, like the more traditional mechanical watch, or have a digital display. These watches are much more accurate than even the most expensive manual wind watches. Learn more about the quartz movement and the quartz revolution.
Return To Top
Tachymeter
A tachymeter (also known as tachometer) measures the speed at which the wearer has traveled over the measured distance found commonly on a chronograph. The wearer starts the chronograph when passing the starting point and stops it when passing the finish. The wearer can then read the speed in units per hour off the tachymeter scale.
Tang Buckle
One of the most common strap closures found. A traditional loop and pin that resembles a belt buckle.
Tank Watch
Designed by Cartier, it is a rectangular watch with bars along the sides the resemble the tracks of a tank used in World War I.
Telemeter
A telemeter determines the distance of an object from the observer by measuring how long it takes sound to travel that distance. Like a tachymeter, it consists of a stopwatch, or chronograph, and a special scale, usually on the outermost edge of the watch dial. One application of a telemeter would be determining the distance of a storm from its observer. The wearer starts the chronograph at the instant the flash of lighting is seen, then stops it when thunder is heard. A reading can then be taken to determine the distance of the storm from the observer in miles on the telemeter scale.
TonneauA barrel shaped case with two convex sides.
Totaliser / TotalizerA mechanism used to track elapsed time, typically found in a subdial.
Tourbillon
A device invented by A.L. Breguet in 1801 to eliminate errors of rate in the vertical positions. It consists of a mobile carriage or cage carrying all the parts of the escapement, with the balance in the center. It is designed to avoid any errors that may be caused by a change in the wearers wrist position. Tourbillons typically rotate one per minute.
Tourbillon
Uni-Directional Rotating Bezel
Typically found on divers’ watches. The bezel only rotates in a counterclockwise direction and is designed to prevent a diver from running out of air by over estimating remaining air supply.
Universal Time
Mean solar time for the Greenwich meridian, but counted from noon to noon.
Vibration
The movement of an oscillating part of the watch, limited by two extreme positions. Generally 5 or 6 vibrations per second, 18,000 or 21,600 per hour, but can also be a higher frequency with as many as seven or ten vibrations, 25,200 or 36,000 per hour. See also: Frequency.
Water-Resistant
The case, crown, push button and glass of a water-resistant watch are made in such a way that no dust or water can penetrate. Watches undergo in-house tests in a laboratory under controlled conditions. Learn more about water resistance markings.
Waterproof
A prohibited term used when describing the water resistance of a watch. No watch is 100% waterproof.
Winding StemAnother word used for the crown. A button found on the side of the case used to wind the mainspring.
World Time ComplicationA dial that contains up to 24 different time zones, found usually on the outer edge of a dial. The time zones are represented by using the names of major cities.
World Time
Yacht Timer
A countdown timer used to sound warning signals during a race, originally developed for the countdown to a boat race.
Edited:
