Hard Metal : A scratch resistant metal comprised of binding several materials, including titanium and tungsten carbide, which are then pressed into an extremely hard metal and polished with diamond powder to add brilliance.
High-Tech Ceramic : Used as a protective shield for spacecraft reentering the earth's atmosphere, high-tech ceramic is polished with diamond dust to create a highly polished finish. Because the ceramic can be injection molded, pieces can be contoured. It has a very smooth surface and is usually found in black, but can be produced in a spectrum of colors.
Horology : The science of time measurement, including the art of designing and constructing the timepieces.
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Index : An hour indicator on an analog watch dial, used instead of numerals.
Integrated Bracelet : A watch bracelet that is integrated into the design of the case.
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Jewels : Synthetic sapphires or rubies that acts as bearings for gears in the mechanical watch, reducing friction.
Jump Hour Indicator : A jump hour indicator takes the place of an hour hand. It usually shows the hours by means of a numeral in a window.
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Kinetic : Based on a revolutionary technology, Kinetic watches run entirely on sell generated energy from natural movement of your wrist. They never need a battery.
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Lap Memory : The ability, in some quartz sport watches, to preserve in the watch's memory the times of laps in a race that have been determined by the lap timer. The wearer can recall these times on a digital display by pushing a button.
Lap Timer : A chronograph function that lets the wearer time segments of a race. At the end of a lap, he/she stops the timer, which then returns to zero to begin timing the next lap.
Limited Editions : A watch style manufactured in a specific amount, often numbered, and available in limited quantities. Limited editions are available from most fine watch manufacturers and may be highly prized by collectors.
Liquid-Crystal Display : (LCD) A digital watch display that shows the time electronically by means of the liquid held in a thin layer between two transparent plates.
Lugs : Projection on the watch face to which the watch band/bracelet is attached.
Luminous Hands : Hands made of skeleton form with the opening filled by a luminous material.
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Main Plate : Base plate on which all the other parts of a watch movement is mounted.
Mainspring : The driving spring of a watch or clock, contained in the barrel.
Marine Chronometer : Highly accurate mechanical or electronic timekeeper enclosed in a box (hence the term box chronometer), used for determining the longitude on board ship. Marine chronometers with mechanical movements are mounted on gimbals so that they remain in the horizontal position is necessary for their precision.
Measurement Conversion : A feature, usually consisting of a graduated scale on the watch's bezel, that lets the wearer translate one type of measurement into another -- miles into kilometers, for instance, or pounds into kilograms.
Mechanical Movement : A movement based on a mainspring, which 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.
Micron : Unit of measurement of the thickness of the gold coating. 1 micron = 1/1000mm.
Military or 24-hour time : When time is measured in 24-hour segments. To convert 12-hour time into 24-hour, simple add 12 to any p.m. time. To convert 24-hour time into 12-hour time, subtract 12 from any time 13 to 24.
Moon-phase : A window in a watch face that shows, which phase the moon, will appear.
Mother-of-Pearl : Iridescent milky interior shell of the freshwater 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.
Movement : The inner mechanism of watch that keeps time and moves the watch's hand, calendar, etc.
Movements are either mechanical or quartz.
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Pedometer : A device that counts the number of strides taken by the wearer by responding to the impact of the wearer's steps.
Perpetual Calendar : A calendar that automatically adjusts for the months' varying length and for leap year. Perpetual calendars, which can be powered by quartz or mechanical movements, are programmed to be accurate until the year 2100. Many watch collectors suggest storing mechanical versions in motorized winding boxes when they aren't being worn in order to maintain the calendar countdown.
Platinum : One of the rarest of precious metals, platinum also is 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. Platinum used in jewelry and watches is at least 85 to 95 percent pure. Many platinum watches are produced in limited editions due to the expense and rarity of the metal.
Power Reserve : The time the watch will run with a fully charged power supply. For mechanical watches it is usually 44 hours. For quartz watches it can vary from 18 moths to 10 years.
Power Reserve Indicator : A feature of a mechanical watch that shows how much longer the watch will operate before it must be wound again.
Pulsimeter : A scale on a chronograph watch for measuring the pulse rate.
Push-piece : Button that is pressed to work a mechanism. (The push-pieces on chronographs, striking watches, alarms, etc.)
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Quartz Crystal : A tiny piece of synthetic quartz that oscillates at the rate of 32.768 times a second, dividing time into equal segments.
Quartz Movement : A movement which allows a watch to keep time without being wound. This technology employs the vibrations of a tiny crystal to maintain timing accuracy. The power comes from a battery that must be replaced about every 1.5 years. In recent years, new quartz technology enables the watch to recharge itself without battery replacement. This power is generated via body motion similar to an automatic mechanical watch, or powered by light through a solar cell, or even by body heat. A digital quartz watch has no mechanical parts. Most quartz movements are made in Hong Kong, Japan or Switzerland.
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Repeater : A device that chimes the time when the wearer pushes a button.
Rose (or pink) Gold : A softly hued gold that contains the same metals 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 additional copper in the alloy.
Rotating Bezel : A bezel (the ring surrounding the watch face) that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions.
Rotor : The part of an automatic watch that winds the movement's main spring.
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Sapphire Crystal : A crystal (the cover that protects the watch face) made of synthetic sapphire, a transparent shatter-resistant, scratch-resistant substance. A sapphire crystal is the most expensive and durable of all of the crystal, approximately three times harder than mineral crystals and 20 times harder than acrylic crystals.
Screw-Lock Crown : A crown that can be screwed into the case to make the watch watertight.
Second Time-Zone Indicator : An additional dial that can be set to the time in another time zone. It lets the wearer keep track of local time and the time in another country simultaneously.
Shock Absorber : Resilient bearing which, in a watch, is intended to take up the shocks received by the balance staff and thus protects its delicate pivots from damage.
Shock Resistance : As defined by the US government regulation, a watch's ability to withstand an impact equal to that of being dropped onto wood floor from a height of 3 feet.
Skeleton Case : A case with a transparent front or back that allows the wearer to view the watch's movement.
Skeleton Hands : Cutout hands showing only the frame.
Slide Rule : A device, consisting of logarithmic or other scale on the outer edge of the watch face , that can be used to do mathematical calculations.
Solar Compass : A compass that lets the wearer determine the geographical poles by means of a rotating bezel. The wearer places the watch so that the hour hand faces the sun. He then takes half the distance between the position and 12 o'clock, and turns the bezel until its "south" marker is at that halfway point. Some quartz watches have solar compasses that show directions on an LCD display.
Solar Powered Batteries : Batteries in a quartz watch that are recharged via solar panels on the watch face.
Split Seconds Hand : Actually two hands, one a flyback hand the other a regular chronograph hand. When the wearer starts the chronograph, both hands move together. To time laps or different finishing times, the wearer can stop the flyback hand independently while the regular chronograph hand keeps moving, in effect"splitting" the hand(s) in two.
Stainless Steel : An extremely durable metal alloy (chromium is a main ingredient) that is virtually immune to rust, discoloration and corrosion; it can be highly polished, thus representing a precious metal. Due to this and the importance of white metal jewelry, steel has become a popular setting for diamonds. Because of its strength, stainless steel is often used even on casebacks of watches made of other metals.
Stepping Motor : The part of a quartz movement that moves the gear train, which in turn moves the watch's hands.
Sterling Silver : A white and highly reflective precious metal. Sterling silver refers to silver that is 92.5 percent pure, which should be stamped on the metal, sometimes accompanied by the initials of the designer or the country of origin as a hallmark. Although less durable than stainless steel and other precious metals, sterling silver is often employed in watches that coordinate or look like sterling silver jewelry. A protective coating may be added to prevent tarnishing.
Stopwatch: A watch with a seconds hand that measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stopwatch function and the timepiece are referred to as a "chronograph".
Subdial : A small dial on the watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on the chronograph or indicating the date.
Swiss Made : A watch is considered Swiss if its movement was assembled, started, adjusted and controlled by the manufacturer in Switzerland.
Swiss A.O.S.C. (Certificate of Origin): A mark identifying a watch that is assembled in Switzerland with components of Swiss origin.
Sweep Seconds-Hand : A seconds-hand that is mounted in the center of the watch dial.
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Tachymeter : A device on the chronograph watch that measure the speed at which the wearer has traveled over a measured distance.
Tank Watch : A rectangular watch designed by Louis Cartier. The bars along the sides of the watch were inspired by the tracks of tanks 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 face.
30-Minute Recorder (or register): A subdial on a chronograph that can time periods of up to 30 minutes.
Timer : Instrument used for registering intervals of time (durations, brief times), without any indication of the time of day.
Titanium : The "space age" metal, often used with a silver-gray appearance. Because it is 30 percent stronger and nearly 50 percent lighter than steel it has been increasingly used in watch making, especially sport watch styles. Its resistance to salt water corrosion makes it particularly useful in diver's watches. Since it can be scratched fairly easy, some manufacturers use a patented-coating to resist scratching. Hypoallergenic.
Tonneau Watch : A watch shaped like a barrel, with two convex sides.
Totalizer : A mechanism that keeps track of elapsed time and display it, usually on a subdial.
Tourbillion : A device in a mechanical watch that eliminates timekeeping errors cause by the slight difference in the rates at which a watch runs in the horizontal and vertical positions. The tourbillion consists of round carriage, or cage, holding the escapement and the balance. It rotates continuously at the rate of once per minute.
Tritium : An isotope of hydrogen that is used to activate the luminous dots or indices on a watch dial. The radioactivity released in this process is too slight to pose a health risk.
Two Tone : A watch that combines two metals, usually yellow gold and stainless steel in the case of fine watches.
12-Hour Recorder (or Register): A subdial on a chronograph that can time periods of up to 12 hours.
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Unidirectional Rotating Bezel : An elapsed time rotating bezel, often found on divers' watches, that moves only in a counterclockwise direction. It is designed to prevent a diver who has unwittingly knocked the bezel off its original position from overestimating his remaining air supply. Because the bezel moves in only one direction, the diver can error only on the side of safety when timing his dive. Many divers' watches are ratcheted, so that they lock into place for greater safety.
Vibration: Movement of a pendulum or other oscillating element, limited by two consecutive extreme positions. The balance of a mechanical watch generally makes five or six vibrations per second (i.e. 18,000 or 21,600 per hour), but that of a high-frequency watch may make seven, eight or even ten vibrations per second (i.e. 25,200, 28,800 or 36, 000 per hour).
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Waterproof : An illegal and misused term. No watch is fully 100 percent waterproof.
Water Resistance : A water resistant watch can handle light moisture, such as a rain or sink splashes, but should not be worn swimming or diving. If the watch can be submerged in water, it must state at what depth it maintains water resistance, i.e. 50 meters or more on most sport watches. Below 200 meters, the watch may be used for skin diving and even scuba diving depending upon the indicated depths.
White Gold : Created from yellow gold by incorporating either nickel or palladium to the alloy to achieve a white color. Most watches made of white gold will be 18k.
Winding : Operation consisting in tightening the mainspring of a watch. This can be done by hand (by means of the crown) or automatically (by means of a rotor, which is caused to swing by the movements of the wearer's arm).
Winding Stem : The button on the right side of the watch case used to wind the mainspring. Also called a "crown".
World Time Dial : A dial, usually on the outer edge of the watch face, that tells the time up to 24 time zones around the world. The time zones are represented by the names of cities printed on the bezel or dial. The wearer reads the hour in a particular time zone by looking at the scale next to the city that the hour hand is pointing to. The minutes are read as normal. Watches with this feature are called "world timers".
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Yacht Timer : A countdown timer that sounds warning signals during the countdown to a boat race.
Yellow Gold : The traditionally popular gold used in all gold, 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.