GLOSSARY
A.
Alarm
A watch complication that sounds an alarm at a predetermined time, or at regular intervals.
Analogue Display
A watch that displays the time with an hour and a minute hand on a dial marked with twelve hour markers.
Antimagnetic
Resistant to magnetization, especially in watches. Magnetic fields are common today, and are found almost everywhere, and they have an adverse effect on mechanical watch movements. For this reason, antimagnetic components are often used in modern movements to minimize any interference.
Anti-reflective coating
A coating on the crystal to minimize or eliminate the reflection of light and thus improve legibility. It is used especially on synthetic sapphire crystals, and may be applied to both sides of the crystal.
Ardillon Buckle
A two piece buckle used to attach a leather strap, like the buckle on a belt. Also known as a Tang buckle.
Atmosphere (ATM)
A unit of measurement used to indicate the water resistance of a watch. One atmosphere is equivalent to 10 metres ( about 33 feet).
Automatic winding
The mechanical automatic movement in an automatic watch is wound by an oscillating rotor weight set in motion by wrist movement. This motion causes the winding of the spring barrel via the gear train. Although automatic winding was invented in the late eighteenth century during the pocket watch era, the significant breakthrough came in the mid-twentieth century with the invention of an automatic movement with a rotor. These days, there are automatic movements with unidirectional winding rotors, and movements with bidirectional winding rotors, depending on the type of gear train employed.
B.
Balance Wheel
The balance wheel may be described as the heart of a movement. It is the recipient of the energy that is used to run the movement, from the escapement mechanism. The balance wheel beats, or oscillates, in a circular motion, normally between five and ten times per second.
Battery
A device that converts chemical energy into electrical energy. Most watch batteries are made of silver oxide, and deliver a charge of 1.5 volts. Lithium batteries are much longer lasting, and deliver a charge of 3 volts.
Bezel
The surface ring on the watch that surrounds and holds the crystal in place. The rotating ratchet bezel in some sport watches function as part of the timing device. If rotating bezels are bidirectional, that is, able to move clockwise and counter-clockwise, they can assist in calculations for elapsed times or for tracking different time zones.
Bracelet
Flexible metal watch band consisting of assembled links, usually in the same style as the case. Detachable links allow one to change the length of the bracelet.
C.
Calendar
A complication on a watch that displays the date and/or the day of the week .
Caliber
A term used to differentiate different types of movements made by the same manufacturer.
Camber
Refers to the degree of curvature of a bezel or an arched dial.
Carat
A unit of gemstone weight, often abbreviated to Ct, (not to be confused with Karat, which indicates the purity of gold and gold alloys).
Case
The body of the watch, which houses the movement and the dial.
Chronograph
A watch that has a stopwatch feature built into the movement.
Chronometer
A high precision watch capable of displaying hours, minutes and seconds, and housing a movement that has been tested over several days, in different positions, and at different temperatures, by an independent, neutral and official authority, the COSC - Contrôle Officiel Suisse des Chronomètres.
Clasp
A hinged metal buckle that attaches to a metal bracelet or leather strap.
Complication
Any feature on a watch beyond the display of the time.
Crown
The small button, pin or knob, often ridges and round, on the side of a watch, used to adjust time and date and to wind the movement on a mechanical watch, thus increasing the power reserve , that is, giving it operating power.
Crystal
The clean cover over the watch face. Three types of crystal typically found on a watch are:
Acrylic crystal – made of an inexpensive plastic that can have shallow scratches buffed out.
Mineral crystal - comprised of several elements that are heat-treated to create unusual hardness for scratch resistance.
Sapphire crystal - the most expensive and durable of the crystals, usually made of synthetic sapphire in modern watches. A non-reflective coating on some sapphire crystals reduces glare.
D.
Day-Date
A complication on a watch that displays the day of the week and the date.
Deployant Buckle
The deployant buckle was invented by Cartier in the early 20th century: a leather strap attached to a folding metal buckle. It is considered more secure to wear than a regular Ardillon buckle, because, should the buckle open inadvertently, the watch is still attached to the wrist. In addition, this type of buckles reduces the wear and tear on the strap as the strap does not need to be bent to fit into the buckle when closing the buckle.
Dial
The watch face, on which the numerals, markers, indices, and/or surface design appear.
Digital Display
Typically, this refers to the LCD display on a quartz watch, though sometimes it is used to refer to oversized numerals indicating date or time on a mechanical watch.
Diver’s Watch
A type of watch that has exceptional water resistance qualities and is usually equipped with a unidirectional diver’s bezel to assist in recording dive time. A diver’s watch may also have a screw-down crown, a helium escape valve, and an extension bracelet.
E.
End of Life (EOL) Indicator
The EOL indicator is a feature on a quartz watch whereby the seconds hand moves in five second intervals (rather than the normal one second interval) when the battery is nearly exhausted. The end of life indicator serves as a reminder to replace the battery before it expires and starts to leak.
F.
Face
The visible front side of the watch, which contains the dial, on which numerals or markers indicate the hours.
Flyback (Retour en vol)
A function particularly useful to pilots that allows the chronograph hand to be reset to zero and immediately started again by pressing once on the push piece.
Frequency
The number of vibrations per second, in hertz (Hz).
G.
GMT (Greenwich Mean Time)
The GMT complication is one in which the timepiece has an additional hour hand which shows the time in two different time zones.
Gold
A yellow, precious metallic element, symbol Au, which is stainless and very malleable, and which is relatively non-reactive, being low in the Electrochemical Series. It is used in alloys to make jewellery, bracelets and watches. The purity of gold in the alloy is indicated in karats (K).
Guilloché
A style of intricate engraving, usually very thin interwoven lines to create texture on a surface, which is popular on watch dials.
H.
Hands
The pointing mechanisms, usually attached at the centre of the dial, indicating hours, minutes and seconds. Sometimes a hand is attached elsewhere to indicate a specific feature or complication of the watch.
Horology
The science of timekeeping and time measurement, and includes the art and science of designing and constructing timepieces.
J.
Jewels
Previously natural gem stones - sapphires or rubies, but in the modern day, synthetic sapphires or rubies, which act as bearings for the gears of a mechanical watch. A quality hand-wound or automatic mechanical watch contains at least 17 jewels.
K.
Karat
A unit of measure for the purity of gold, sometimes abbreviated to K or Kt, (not to be confused with Carat, a measure of gem stone weight). 24K gold is pure gold; 18K gold is 75% pure, and so on.
L.
Lugs
Lugs are the extensions on either side of the bezel, on the case, to which the strap or bracelet is attached.
Luminous
Luminous pigment applied to hands and markers, such that they glow in the dark after having been subjected to light rays.
M.
Manual
A hand-wound mechanical wristwatch.
Mechanical Movement
A movement that operates by means of a mainspring and which is wound by hand. When wound, the watch works through the energy of the mainspring, which slowly unwinds in an even motion. An automatic mechanical movement requires very little winding because of the rotor, which winds the mainspring with the motion of one's wrist.
Mineral Crystal
Watch crystal made of glass that has been tempered to increase its scratch resistance.
Minute Repeater
A complication on a watch that can indicate the time in hours, quarters of an hour, or seconds, by means of a push-piece.
Moon Phase
A complication on a watch in which an indicator shows the phases of the moon. (A regular rotation of the moon around the earth takes 29 days, 12 hours and 44 minutes approximately). Once set, the moon phase indicator accurately displays the phase of the moon.
Mother-of-pearl
The iridescent, milky, interior shell of a freshwater mollusc that is sliced thinly and used on watch dials. Whilst most have a milky white lustre, mother-of-pearl also comes in other colours such as silver-grey, grey-blue, pink and salmon, and various hues of each of these.
Movement
The complex working part of a watch - the "engine" so to speak. A movement may be either mechanical (analogue), or quartz (electronic).
O.
Oscillation
The movement of the balance wheel from one extreme to the other, and back again, at a regular speed.
P.
Perpetual Calendar
A type of calendar complication that automatically adjusts for the varying lengths of months, including indicating February 29th in each leap year.
Plating
A coating of a metal base with another metal. In watchmaking, a stainless steel base may be coated with gold 7 to 20 microns thick, either through electroplating or ion-plating.
Platinum
One of the rarest precious metals, platinum is also one of the strongest and heaviest, making it a popular choice for setting in expensive gemstone jewellery and watches. It has a rich, white lustre and may be said to have an understated look. Platinum is hypo-allergenic and tarnish resistant and is 80-90% pure when used in jewellery and watches.
Power Reserve
The time the watch will run with a fully charged power supply. For mechanical watches, it is usually about 38-44 hours.
Q.
Quartz
A quartz movement, usually the most accurate type of movement. It uses a battery for its power.
R.
Ratchet Bezel
A bezel ring which can either turn one way (counter-clockwise), or both ways, and generally clicks into place.
Rattrapante (Split-Second Chronograph)
A second chronograph 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 after resetting.
Retour en Vol (Flyback)
A function particularly useful to pilots that allows the chronograph hand to be reset to zero and immediately started again by pressing once on the push piece.
Rose Gold
A softly hued gold that contains the same materials as yellow gold but with a higher concentration of copper in the alloy, often seen in retro-styling or in tricolor gold versions.
S.
Sapphire Crystal
A synthetic corundum crystal with a hardness second only to diamond. Transparent sapphire is used for scratch-resistant watch crystals.
Screw Down Crown
A crown that helps with water resistance by sealing the crown against the case.
Seal
Synthetic gaskets that seal the joints between parts of the case to keep out moisture.
Shock Resistance
The ability to withstand normal wear and tear, even during strenuous sport activities.
Skeleton Movement
A watch with a skeletonized movement, cut-aways, exposing the working mechanism of the movement.
Slide Rule Bezel
A rotating bezel that is printed with a logarithmic scale, and/or other mathematical scales.
Split-Second Chronograph (Rattrapante)
A second chronograph 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, after resetting.
Stainless Steel
An extremely durable metal alloy, in which chromium is a main ingredient. It is immune to rust, discoloration, and corrosion. Stainless steel can be highly polished, thus resembling a precious metal. Because of its strength, it is often used on watch case backs that are made of other metals.
Sterling Silver
A white and highly reflective precious metal. Sterling refers to silver that is 92.5% pure, which should be stamped on the metal, sometimes accompanied by the initials of the designer or country of origin as a hallmark. Although less durable than stainless steel and other precious metals, sterling silver is often used in watches.
Strap
A watch band made of leather, plastic or fabric.
Subdial
A small dial used for several purposes, such as keeping track of elapsed minutes, hours or seconds on a chronograph, or indicating the date.
Sun/Moon Indicator
A wheel on a watch partially visible through a cut-out window indicating a sun and a moon on a 24-hour basis.
T.
Tachymeter (also tachometer)
A watch function that measures the speed at which the wearer moves.
Tang
Classic belt buckle, also known as an Ardillon, used to fasten a watch strap.
Tank Watch
A rectangular watch with heavier bars on either side of the dial, inspired by the tank tracks of World War I, and first created by Louis Cartier.
Telemeter
A watch function that finds the distance of an object from the wearer by measuring how long it takes sound to travel that distance. Like a tachymeter, a telemeter consists of a stopwatch function and a special scale on the dial of a chronograph.
Titanium
The “space age” metal, often with a silvery gray appearance. Because it is 30 percent stronger and nearly 50 percent lighter than steel, it has been increasingly used in watchmaking, especially sport-style watches. Its resistance to salt water corrosion makes it particularly useful in diver’s watches. As it can be scratched fairly easily, some manufacturers use a patented-coating to protect the metal.
Tonneau Case
A watch with a barrel-shaped case with two convex sides.
Tourbillon
A device in some mechanical watches, invented by French watchmaker Abraham-Louis Breguet in the eighteenth century as an attempt to eliminate timekeeping errors caused by slight variations from shifts in gravity when a watch changes position during use. The round carriage or “cage” of the tourbillon holds the mechanisms that rotate the wheels, and thus the hands of the watch, in a continuous rate of one revolution per minute. Tourbillon is French for whirlwind.
V.
Vibration
The balance of a mechanical watch generally makes five vibrations per second, equivalent to 18,000 vibrations per hour (2,5 Hz). More accurate mechanical watches make ten vibrations per second - 36,000 vibrations per hour (5 Hz).
Quartz watches make 17,77 vibrations per second - 64,000 vibrations per hour (32 Hz).
W.
Waterproof
An much misused term in horology. Watches are generally water-resistant to certain depths, depending on the manufacture.
Water Resistant
A watch bearing the inscription “water-resistant” on its case back can withstand light moisture, such as a rainstorm or sink splashes but should not be worn swimming or diving.
Watches come in varying degrees of water resistance:
Water resistant: can withstand splashes of water or light rain, but should not be worn while showering or swimming
Water tested to 50 meters (165 feet): can withstand rainfall, but should not be worn while showering or swimming
Water resistant to 100 meters (330 feet): suitable for shallow water swimming and snorkeling
Water resistant to 150 meters (500 feet): suitable for swimming,board diving and snorkeling
Water resistant to 200 meters (660 feet): suitable for scuba diving
Water resistant to 1,000 meters (3,300 feet): suitable for deep sea diving.
White Gold
Created from yellow gold by adding either nickel or palladium to the alloy to achieve a white color. Most watches made of white gold are 18K.
World Timer
A watch with a dial that indicates up to 24 time zones around the world, usually found on the outer edge of the face or sometimes on the bezel. Time zones around the world are indicated by major cities.
Y.
Yellow Gold
The traditional and popular colour gold used in all gold or gold and stainless steel or other precious metal combinations. Yellow gold watches may be found in 14K or, as is the case with most European manufacturers, 18K.
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Alarm
A watch complication that sounds an alarm at a predetermined time, or at regular intervals.
Analogue Display
A watch that displays the time with an hour and a minute hand on a dial marked with twelve hour markers.
Antimagnetic
Resistant to magnetization, especially in watches. Magnetic fields are common today, and are found almost everywhere, and they have an adverse effect on mechanical watch movements. For this reason, antimagnetic components are often used in modern movements to minimize any interference.
Anti-reflective coating
A coating on the crystal to minimize or eliminate the reflection of light and thus improve legibility. It is used especially on synthetic sapphire crystals, and may be applied to both sides of the crystal.
Ardillon Buckle
A two piece buckle used to attach a leather strap, like the buckle on a belt. Also known as a Tang buckle.
Atmosphere (ATM)
A unit of measurement used to indicate the water resistance of a watch. One atmosphere is equivalent to 10 metres ( about 33 feet).
Automatic winding
The mechanical automatic movement in an automatic watch is wound by an oscillating rotor weight set in motion by wrist movement. This motion causes the winding of the spring barrel via the gear train. Although automatic winding was invented in the late eighteenth century during the pocket watch era, the significant breakthrough came in the mid-twentieth century with the invention of an automatic movement with a rotor. These days, there are automatic movements with unidirectional winding rotors, and movements with bidirectional winding rotors, depending on the type of gear train employed.
B.
Balance Wheel
The balance wheel may be described as the heart of a movement. It is the recipient of the energy that is used to run the movement, from the escapement mechanism. The balance wheel beats, or oscillates, in a circular motion, normally between five and ten times per second.
Battery
A device that converts chemical energy into electrical energy. Most watch batteries are made of silver oxide, and deliver a charge of 1.5 volts. Lithium batteries are much longer lasting, and deliver a charge of 3 volts.
Bezel
The surface ring on the watch that surrounds and holds the crystal in place. The rotating ratchet bezel in some sport watches function as part of the timing device. If rotating bezels are bidirectional, that is, able to move clockwise and counter-clockwise, they can assist in calculations for elapsed times or for tracking different time zones.
Bracelet
Flexible metal watch band consisting of assembled links, usually in the same style as the case. Detachable links allow one to change the length of the bracelet.
C.
Calendar
A complication on a watch that displays the date and/or the day of the week .
Caliber
A term used to differentiate different types of movements made by the same manufacturer.
Camber
Refers to the degree of curvature of a bezel or an arched dial.
Carat
A unit of gemstone weight, often abbreviated to Ct, (not to be confused with Karat, which indicates the purity of gold and gold alloys).
Case
The body of the watch, which houses the movement and the dial.
Chronograph
A watch that has a stopwatch feature built into the movement.
Chronometer
A high precision watch capable of displaying hours, minutes and seconds, and housing a movement that has been tested over several days, in different positions, and at different temperatures, by an independent, neutral and official authority, the COSC - Contrôle Officiel Suisse des Chronomètres.
Clasp
A hinged metal buckle that attaches to a metal bracelet or leather strap.
Complication
Any feature on a watch beyond the display of the time.
Crown
The small button, pin or knob, often ridges and round, on the side of a watch, used to adjust time and date and to wind the movement on a mechanical watch, thus increasing the power reserve , that is, giving it operating power.
Crystal
The clean cover over the watch face. Three types of crystal typically found on a watch are:
Acrylic crystal – made of an inexpensive plastic that can have shallow scratches buffed out.
Mineral crystal - comprised of several elements that are heat-treated to create unusual hardness for scratch resistance.
Sapphire crystal - the most expensive and durable of the crystals, usually made of synthetic sapphire in modern watches. A non-reflective coating on some sapphire crystals reduces glare.
D.
Day-Date
A complication on a watch that displays the day of the week and the date.
Deployant Buckle
The deployant buckle was invented by Cartier in the early 20th century: a leather strap attached to a folding metal buckle. It is considered more secure to wear than a regular Ardillon buckle, because, should the buckle open inadvertently, the watch is still attached to the wrist. In addition, this type of buckles reduces the wear and tear on the strap as the strap does not need to be bent to fit into the buckle when closing the buckle.
Dial
The watch face, on which the numerals, markers, indices, and/or surface design appear.
Digital Display
Typically, this refers to the LCD display on a quartz watch, though sometimes it is used to refer to oversized numerals indicating date or time on a mechanical watch.
Diver’s Watch
A type of watch that has exceptional water resistance qualities and is usually equipped with a unidirectional diver’s bezel to assist in recording dive time. A diver’s watch may also have a screw-down crown, a helium escape valve, and an extension bracelet.
E.
End of Life (EOL) Indicator
The EOL indicator is a feature on a quartz watch whereby the seconds hand moves in five second intervals (rather than the normal one second interval) when the battery is nearly exhausted. The end of life indicator serves as a reminder to replace the battery before it expires and starts to leak.
F.
Face
The visible front side of the watch, which contains the dial, on which numerals or markers indicate the hours.
Flyback (Retour en vol)
A function particularly useful to pilots that allows the chronograph hand to be reset to zero and immediately started again by pressing once on the push piece.
Frequency
The number of vibrations per second, in hertz (Hz).
G.
GMT (Greenwich Mean Time)
The GMT complication is one in which the timepiece has an additional hour hand which shows the time in two different time zones.
Gold
A yellow, precious metallic element, symbol Au, which is stainless and very malleable, and which is relatively non-reactive, being low in the Electrochemical Series. It is used in alloys to make jewellery, bracelets and watches. The purity of gold in the alloy is indicated in karats (K).
Guilloché
A style of intricate engraving, usually very thin interwoven lines to create texture on a surface, which is popular on watch dials.
H.
Hands
The pointing mechanisms, usually attached at the centre of the dial, indicating hours, minutes and seconds. Sometimes a hand is attached elsewhere to indicate a specific feature or complication of the watch.
Horology
The science of timekeeping and time measurement, and includes the art and science of designing and constructing timepieces.
J.
Jewels
Previously natural gem stones - sapphires or rubies, but in the modern day, synthetic sapphires or rubies, which act as bearings for the gears of a mechanical watch. A quality hand-wound or automatic mechanical watch contains at least 17 jewels.
K.
Karat
A unit of measure for the purity of gold, sometimes abbreviated to K or Kt, (not to be confused with Carat, a measure of gem stone weight). 24K gold is pure gold; 18K gold is 75% pure, and so on.
L.
Lugs
Lugs are the extensions on either side of the bezel, on the case, to which the strap or bracelet is attached.
Luminous
Luminous pigment applied to hands and markers, such that they glow in the dark after having been subjected to light rays.
M.
Manual
A hand-wound mechanical wristwatch.
Mechanical Movement
A movement that operates by means of a mainspring and which is wound by hand. When wound, the watch works through the energy of the mainspring, which slowly unwinds in an even motion. An automatic mechanical movement requires very little winding because of the rotor, which winds the mainspring with the motion of one's wrist.
Mineral Crystal
Watch crystal made of glass that has been tempered to increase its scratch resistance.
Minute Repeater
A complication on a watch that can indicate the time in hours, quarters of an hour, or seconds, by means of a push-piece.
Moon Phase
A complication on a watch in which an indicator shows the phases of the moon. (A regular rotation of the moon around the earth takes 29 days, 12 hours and 44 minutes approximately). Once set, the moon phase indicator accurately displays the phase of the moon.
Mother-of-pearl
The iridescent, milky, interior shell of a freshwater mollusc that is sliced thinly and used on watch dials. Whilst most have a milky white lustre, mother-of-pearl also comes in other colours such as silver-grey, grey-blue, pink and salmon, and various hues of each of these.
Movement
The complex working part of a watch - the "engine" so to speak. A movement may be either mechanical (analogue), or quartz (electronic).
O.
Oscillation
The movement of the balance wheel from one extreme to the other, and back again, at a regular speed.
P.
Perpetual Calendar
A type of calendar complication that automatically adjusts for the varying lengths of months, including indicating February 29th in each leap year.
Plating
A coating of a metal base with another metal. In watchmaking, a stainless steel base may be coated with gold 7 to 20 microns thick, either through electroplating or ion-plating.
Platinum
One of the rarest precious metals, platinum is also one of the strongest and heaviest, making it a popular choice for setting in expensive gemstone jewellery and watches. It has a rich, white lustre and may be said to have an understated look. Platinum is hypo-allergenic and tarnish resistant and is 80-90% pure when used in jewellery and watches.
Power Reserve
The time the watch will run with a fully charged power supply. For mechanical watches, it is usually about 38-44 hours.
Q.
Quartz
A quartz movement, usually the most accurate type of movement. It uses a battery for its power.
R.
Ratchet Bezel
A bezel ring which can either turn one way (counter-clockwise), or both ways, and generally clicks into place.
Rattrapante (Split-Second Chronograph)
A second chronograph 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 after resetting.
Retour en Vol (Flyback)
A function particularly useful to pilots that allows the chronograph hand to be reset to zero and immediately started again by pressing once on the push piece.
Rose Gold
A softly hued gold that contains the same materials as yellow gold but with a higher concentration of copper in the alloy, often seen in retro-styling or in tricolor gold versions.
S.
Sapphire Crystal
A synthetic corundum crystal with a hardness second only to diamond. Transparent sapphire is used for scratch-resistant watch crystals.
Screw Down Crown
A crown that helps with water resistance by sealing the crown against the case.
Seal
Synthetic gaskets that seal the joints between parts of the case to keep out moisture.
Shock Resistance
The ability to withstand normal wear and tear, even during strenuous sport activities.
Skeleton Movement
A watch with a skeletonized movement, cut-aways, exposing the working mechanism of the movement.
Slide Rule Bezel
A rotating bezel that is printed with a logarithmic scale, and/or other mathematical scales.
Split-Second Chronograph (Rattrapante)
A second chronograph 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, after resetting.
Stainless Steel
An extremely durable metal alloy, in which chromium is a main ingredient. It is immune to rust, discoloration, and corrosion. Stainless steel can be highly polished, thus resembling a precious metal. Because of its strength, it is often used on watch case backs that are made of other metals.
Sterling Silver
A white and highly reflective precious metal. Sterling refers to silver that is 92.5% pure, which should be stamped on the metal, sometimes accompanied by the initials of the designer or country of origin as a hallmark. Although less durable than stainless steel and other precious metals, sterling silver is often used in watches.
Strap
A watch band made of leather, plastic or fabric.
Subdial
A small dial used for several purposes, such as keeping track of elapsed minutes, hours or seconds on a chronograph, or indicating the date.
Sun/Moon Indicator
A wheel on a watch partially visible through a cut-out window indicating a sun and a moon on a 24-hour basis.
T.
Tachymeter (also tachometer)
A watch function that measures the speed at which the wearer moves.
Tang
Classic belt buckle, also known as an Ardillon, used to fasten a watch strap.
Tank Watch
A rectangular watch with heavier bars on either side of the dial, inspired by the tank tracks of World War I, and first created by Louis Cartier.
Telemeter
A watch function that finds the distance of an object from the wearer by measuring how long it takes sound to travel that distance. Like a tachymeter, a telemeter consists of a stopwatch function and a special scale on the dial of a chronograph.
Titanium
The “space age” metal, often with a silvery gray appearance. Because it is 30 percent stronger and nearly 50 percent lighter than steel, it has been increasingly used in watchmaking, especially sport-style watches. Its resistance to salt water corrosion makes it particularly useful in diver’s watches. As it can be scratched fairly easily, some manufacturers use a patented-coating to protect the metal.
Tonneau Case
A watch with a barrel-shaped case with two convex sides.
Tourbillon
A device in some mechanical watches, invented by French watchmaker Abraham-Louis Breguet in the eighteenth century as an attempt to eliminate timekeeping errors caused by slight variations from shifts in gravity when a watch changes position during use. The round carriage or “cage” of the tourbillon holds the mechanisms that rotate the wheels, and thus the hands of the watch, in a continuous rate of one revolution per minute. Tourbillon is French for whirlwind.
V.
Vibration
The balance of a mechanical watch generally makes five vibrations per second, equivalent to 18,000 vibrations per hour (2,5 Hz). More accurate mechanical watches make ten vibrations per second - 36,000 vibrations per hour (5 Hz).
Quartz watches make 17,77 vibrations per second - 64,000 vibrations per hour (32 Hz).
W.
Waterproof
An much misused term in horology. Watches are generally water-resistant to certain depths, depending on the manufacture.
Water Resistant
A watch bearing the inscription “water-resistant” on its case back can withstand light moisture, such as a rainstorm or sink splashes but should not be worn swimming or diving.
Watches come in varying degrees of water resistance:
Water resistant: can withstand splashes of water or light rain, but should not be worn while showering or swimming
Water tested to 50 meters (165 feet): can withstand rainfall, but should not be worn while showering or swimming
Water resistant to 100 meters (330 feet): suitable for shallow water swimming and snorkeling
Water resistant to 150 meters (500 feet): suitable for swimming,board diving and snorkeling
Water resistant to 200 meters (660 feet): suitable for scuba diving
Water resistant to 1,000 meters (3,300 feet): suitable for deep sea diving.
White Gold
Created from yellow gold by adding either nickel or palladium to the alloy to achieve a white color. Most watches made of white gold are 18K.
World Timer
A watch with a dial that indicates up to 24 time zones around the world, usually found on the outer edge of the face or sometimes on the bezel. Time zones around the world are indicated by major cities.
Y.
Yellow Gold
The traditional and popular colour gold used in all gold or gold and stainless steel or other precious metal combinations. Yellow gold watches may be found in 14K or, as is the case with most European manufacturers, 18K.
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