Acrylic Crystal
Made of an inexpensive plastic that can have shallow scratches buffed out.
A watch complication that sounds an alarm at a preset time or at regular intervals.
A watch that displays the time with an hour and a minute hand on a dial marked with twelve hour markers.
Ardillon Buckle
Regular two piece buckle used to attach a leather strap, like the buckle on a belt.
Atmosphere (ATM)
A unit of measurement used to indicate the water resistance of a watch. One atmosphere equals 10 meters (33 feet).
A mechanical watch movement that is equipped with an oscillating rotor that spins as the wearer's wrist moves. The movement of the rotor winds the watch.
The heart of the movement that receives the energy to run from the escapement. The balance wheel beats, or oscillates, in a circular motion between five and ten times per second.
Any non-precious metal.
A device that converts chemical energy into electricity. Most watch batteries are silver oxide type delivering 1.5 volts. Much longer lasting lithium batteries are 3 volts.
The surface ring on the watch that surrounds and holds the crystal in place. A rotating ratchet bezel moves in some sport watches as part of the timing device. If rotating bezels are bidirectional (able to move clockwise or counter-clockwise) they can assist in calculations for elapsed times or for tracking different time zones.
Flexible metal band consisting of assembled links, usually in the same style as the case. Detachable links change the length of the bracelet.
Cabochon Crown
A winding crow set with a precious or semiprecious stone, usually sapphire, spinnel, or diamond.
A complication on a watch that displays the date.
A term used to differentiate different types of movements made by the same manufacturer.
Cambered
Refers to a curved or arched dial or bezel.
Carat (Karat)
A unit of gold fineness (and gemstone weight). 24K is pure gold, whereas 18K gold is 75% pure.
The body of the watch that contains the movement and dial.
A watch that has a stop watch feature built into the movement.
A movement certified by an independent testing agency called C.O.S.C. (Contrôle Officiel Suisse des Chronomètres) and is known to be 99% accurate over a fifteen day period in a variety of simulated wearing positions and different temperatures.
Refers to a hinged metal buckle that attaches a metal bracelet or leather strap.
Any feature on a watch beyond the display of the time.
A feature found predominantly on quartz watches that allows the user to set an allotted time in hours and minutes and have an alarm ring when that time period expires.
The round knob on the side of watch used to adjust time and date and wind the movement on a mechanical watch, giving it operating power.
The clean cover over the watch face. Three types of crystals are commonly found in watches:
1. Acrylic crystal – made of an inexpensive plastic that can have shallow scratches buffed out. 2. Mineral crystal- comprised of several elements that are heat-treated to create unusual hardness for scratch resistance. 3. Sapphire crystal- the most expensive and durable of the crystals. A non-reflective coating on some sport styles prevents glare.
Complication on a watch that displays the day and date.
Deployant Buckle
Invented by Cartier in the early 20th century, a leather strap attached to a folding metal buckle that is considered more secure to wear than a regular Ardillon buckle. Should the buckle open up, the watch is still attached to the wrist.
The watch face. The numerals, indices, or surface design are usually applied; others have been printed on.
Can refer to either a LCD display on a quartz watch or oversized numerals indicating date or time on a mechanical watch.
Diver's Watch
A type of watch that has exceptional water resistance and is usually equipped with a unidirectional diver's bezel to assist in recording dive time. A diver's watch may also have a helium escape valve, screw down crown, and extension bracelet.
End of Life (EOL) Indicator
A feature on a quartz watch that causes the second hand to jump in five second intervals when the battery is nearly exhausted. The end of life indicator serves as a reminder to replace the battery when necessary.
The visible side of the watch where the dial is contained; most are printed with Arabic or Roman numerals.
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.
The number of vibrations per second, in hertz (Hz).
GMT (Greenwich Mean Time)
The GMT has an additional hour hand that shows two different time zones.
A yellow precious metal that is stainless and very malleable. It is used in alloys to make jewelry, bracelets and watches. The portion of gold in the alloy is indicated in carats (K).
Guilloché
A style of intricate engraving (usually very thin lines interwoven to create a surface texture) that is popular on watch dials.
The pointing device anchored at the center of and circling around the dial indicating hours, minutes, seconds and any other special features of the watch.
High-tech Ceramic
Used as a protective shield for space crafts reentering the earth's atmosphere, high-tech ceramic is polished with diamond dust to create a highly polished finish. As the ceramic can be injection molded, pieces can be contoured. It has a very smooth surface, usually found in black but can be produced in a spectrum of colors.
The science of time measurement, including the art of designing and constructing timepieces.
Synthetic sapphires or rubies that act as bearings for gears of a mechanical watch. A quality hand wound or automatic mechanical watch contains at least 17 jewels.
Karat (Carat)
Extensions on either side of the bezel where the bracelet or strap is attached.
Self-illuminating paint used on hands and markers.
A hand-wound mechanical watch.
Mechanical Movement
A movement based on a mainspring that is wound by hand. When wound, it slowly unwinds the spring in an even motion. An automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist.
Military time (24-hour time)
Time measured in 24-hour segments. To convert 12-hour time into 24-hour time, simply add 12 to any p.m. time. To convert 24-hour time into 12-hour time, subtract 12 from any time from 13 to 24.
Watch glass that has been tempered to increase its scratch resistance.
A complication on a watch that can strike the time in hours, quarters, or seconds by means of a push piece.
An indicator that keeps track of the moon's phases. A regular rotation of the moon is once around the earth every 29 days, 12 hours, and 44 minutes. Once set, the moonphase indicator accurately displays the phase of the moon.
An iridescent, milky interior shell of the fresh water mollusk that is sliced thin and used on watch dials. While most have a milky white luster, mother-of-pearl also comes in other colors such as silvery gray, gray blue, pink, and salmon.
The engine of the watch, a movement is either quartz or mechanical.
The travel of the balance wheel from one extreme to the other and back again.
A type of calendar complication that automatically adjusts for months of different lengths and indicates February 29 in each leap year.
Pink (or rose) Gold
A softly hued gold that contains the same materials as yellow gold but with a higher concentration of copper in the alloy. A popular color in Europe, rose gold in watches is often seen in retro styling or in tricolor gold versions. Some 18K red gold watches achieve their color from adding more copper in the alloy.
A coating of a metal base with another metal. In watchmaking, a stainless steel base is coated with gold 7 to 20 microns thick.
One of the rarest precious metals, platinum is also one of the strongest and heaviest, making it a popular choice for setting gemstone jewelry and watches. It has a rich, white luster and an understated look. Platinum is hypoallergenic and tarnish resistant and is 85-95% pure when used in jewelry and watches. Many platinum watches are produced in limited editions due to the expense and rarity of the metal.
The time the watch will run with a fully charged power supply. For mechanical watches, it is usually 44 hours whereas for quartz watches it can vary from 18 months to 10 years.
A quartz movement, usually the most accurate type of movement, uses a battery for its power.
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.
Retour en vol (Flyback)
Rose (or pink) Gold
Synthetic corundum crystal with a hardness second only to diamond. Transparent sapphire is used for scratch-resistant watch crystals.
A crown that helps with water resistance by sealing the crown against the case.
Synthetic gaskets that seal the joints between parts of the case to keep out moisture.
The ability to withstand normal wear and tear, even during strenuous sport activities.
Skeleton Movement
A watch with no dial that exposes the movement.
Slide Rule Bezel
A rotating bezel that is printed with a logarithmic scale and others and is used with fixed rules of mathematics.
Split-Second Chronograph (Rattrapante)
An extremely durable metal alloy (chromium is a main ingredient) that 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 casebacks that are made of other metals.
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 that look like sterling jewelry. A protective coating may be added to prevent tarnish.
A watch band made of leather, plastic or fabric.
Subdial
A small dial used for several purposes, such as keeping track of elapsed minutes or hours 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.
Tachymeter (also tachometer)
A watch function that measures the speed at which the wearer moves.
Classic belt buckle, also known as an Ardillon.
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.
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.
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 watch styles. Its resistance to salt water corrosion makes it particularly useful in diver's watches. Since it can be scratched fairly easily, some manufacturers use a patented-coating to resist scratching.
Tonneau Case
A watch with a barrel-shaped case with two convex sides.
A device in some mechanical watches that attempts 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 once per minute.
A swing of the balance. A watch vibrating 18,000 times an hour beats five times a second.
An illegal and misused term; no watch is fully 100 percent waterproof.
A watch bearing the inscription "water resistant" on its caseback can withstand light moisture, such as a rainstorm or sink splashes but should not be worn swimming or diving.
Watches come in different water resistant depths and diver's depths:
Water resistant: Withstands splashes of water or rain but should not be worn while swimming or diving
Water tested to 50 meters (165 feet): Suitable for showering or swimming in shallow water
Water resistant to 100 meters (330 feet): Suitable for swimming or snorkeling
Water resistant to 150 meters (500 feet): Suitable for snorkeling.
Water resistant to 200 meters (660 feet): Suitable for scuba diving
Water resistant to 1000 meters (3300 feet): Suitable for professional deep sea diving
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.
The traditional and popular color 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 found from most European manufacturers, 18K.