Glossary
A
Accuracy: Refers to rate constancy of a watch, not only on whether it is showing the exact time. A watch gaining or loosing exactly the same amount every day is considered accurate. It is considered "normal" for mechanical or automatic watches to gain/lose 4-6 minutes per day.
Acrylic Crystal: Sometimes referred to as Hesolite, an acrylic crystal is composed of plastic composite that is generally less expensive and less durable than a sapphire or a mineral crystal. Benefits of an acrylic crystal are that it flexes rather than shatters on impact. It also produces little glare under bright light and can be polished easily. Most watches produced since the 1930's use acrylic crystals.
Analog Watch: A watch with a dial, hands, and numbers or markers that present a total display of 12-hours.
Aperture: Small opening. The dials of some watches (in French: montres à guichet) have apertures in which certain indications are provided (e.g. the date, the hour, etc).
Atmosphere (Atm): Unit of pressure used in watch making to indicate water resistance.
Atomic Time Standard: Provided by the U.S. National Institute of Standards and Technology, Time and Frequency Division, Boulder, Colorado, atomic time is measured through vibrations of atoms in a metal isotope that resembles mercury. The result is extremely accurate time that can be measured on instruments. Radio waves transmit this exact time throughout North America and some 'atomic' watches can receive them and correct to the exact time. To synchronize your watch with atomic standard time, call (303) 499-7111.
Automatic Movement / Automatic Winding(also called self-winding): A mechanically powered watch that is wound by the motion of the wearer's arm rather than through turning the winding stem (manual mechanical). In response to this motion, a rotor turns and winds the watch's mainspring. Most automatic watches have up to 36 hours of power reserve. If an automatic watch is not worn for a day or two, it will wind down and need to be wound by hand to get it started again.
B
Band: A generic term used to refer to the band that holds a watch on your wrist. The preferred terms bracelet and strap, clearly describe the two major types
Balance: Mechanical watches are regulated with the balance and balance spring. The mainspring provides energy. The hairspring, coupled to the balance, makes it swing to and fro, dividing into equal parts. Each to and fro of the balance is called oscillation. One oscillation equals 2 vibrations. (Heart of the mechanical watch)
Balance Spring: The (or hair spring) is attached to the balance and cock, and made of metal alloys. Its length determines the amount that the balance regularly oscillates: the shorter the spring the faster the watch runs. It returns the balance wheel back to a neutral position.
Balance Wheel: Regulating organ of the watch, vibrating on a spiral hairspring. Lengthening and shortening of the balance spring makes the balance wheel go faster or slower to advance or retard the watch.
Battery: A device that converts chemical energy into electricity. Most watch batteries are the silver oxide type, delivering 1.5 volts. Much longer-lasting lithium batteries deliver 3 volts.
Battery-less Quartz: Also known under various marketing names, including Kinetic (Seiko), Omega-matic (Omega), and Auto quartz (Invicta). Terms for the modern hybrid watch technology of using a quartz movement powered by a small electric current generator operated by a rotor. Electricity generated from the rotor's movement is stored in a capacitor, rechargeable battery, or similar means to keep the watch running. So, like an automatic watch, these also must be worn regularly to keep up their electrical power reserve.
Bezel: The ring around the top of the crystal. Generally hold the glass or crystal in place. A rotating ratchet bezel moves in some watches as part of a complication. Rotating bezels either rotate clockwise, counter clockwise, or both to assist in calculations.
Bi-Directional Rotating Bezel: A bezel that rotates both clockwise and counter clockwise.
Bracelet: A bracelet is the flexible metal band consisting of assembled links, usually in the same style as the watchcase. Detachable links change the length of the bracelet. Bracelets can be made of stainless steel, sterling silver, gold or a combination.
Buttons: Push piece controls, usually at 2 o"clock and/or 4 o"clock on the dial to control specific functions such as the chronograph or the alarm.
C
Calendar: The calendar mechanism or function on a watch can consist of a date only showing in a window through to a triple calendar, showing the date, day and month. A combination of dial cut outs and pointer hands may be used. The most complicated calendar mechanisms may be mechanically programmed to show the year and months including those with less that 31 days; leap years can also be mechanically allowed for. Sometimes referred to as a perpetual calendar.
Case or Watchcase: The metal housing that contains the internal parts of a watch. Stainless steel is the most typical metal used, but titanium, gold, silver and platinum can also be used.
Chronograph: A multifunction sport watch with a stopwatch function. Most have two or three sub dials, or mini dials, for measuring minutes and hours. When used in conjunction with specialized scales on the watch dial it can perform many different functions, such as determining speed or distance (see "tachometer" and "telemeter"). Some can time more than one event at a time (see "flyback hand" and "split seconds hand"). Not to be confuse with "chronometer" which is a timepiece that has met certain high standards of accuracy set by an official watch institute of Switzerland.
Chronometer: A chronometer is a high-precision watch capable of displaying the seconds and housing a movement that has been tested over several days, in different positions and at different temperatures, by an official neutral body (COSC). Each chronometer is unique, identified by a number engraved on its movement and a certification number given by the COSC. Each movement is individually tested for several consecutive days, in 5 positions and at 3 temperatures. Each movement is individually measured. Any watch with the denomination "chronometer" is provided with a certified movement.
Clasp: Used to secure the bracelet or strap of a wristwatch, to the wrist. There are three basic types of clasps; fold-over clasp, jewelry clasp and butterfly-clasp (aka deployant/deployment buckle, hidden deployant buckle, hidden double-locking clasp).
Complication: Any "function" added to a watch, such as a minute repeater, countdown timer, stop watch, altimeter, asthometer, pulsometer, calendar, moon phase indicator, split second chronograph, power reserve indicator, alarm, etc.
C.O.S.C. Controle Officiel Suisse des Chronometres (Official Swiss Chronometer Testing Institute):
Crown: Knob used to wind a mechanical watch and to set the time and/or calendar of a watch.
Cyclops: Small lens on the crystal to magnify the date.
D
Day/Date Watch: watch that indicates not only the date but also the day of the week.
Deployment Buckle (Fold over): A three-folding enclosure that secures the two ends of the bracelet and allows enough room for placing the watch on the wrist when fully deployed. When closed, the buckle covers the two-piece folding mechanism.
Dial: The dial, often referred to as the face is usually marked with numbers or batons to which the hands point in order for the wearer to tell the correct time. Dials may be minimalist with no markers at all or extremely complex as in the case of pilots' chronographs. Dials may be decorated with patterns or in some cases with precious stones.
Diver's Watch: Divers' watches traditionally feature a graduated, rotating bezel, screw down winding crown, and caseback. Must be water resistant to at least 200m or 660 feet.
Dual Time/Second Time Zone Bezel: A rotating bezel, which can be used to display a separate time zone distinct from that shown on the dial.
Dual Time: A watch that measures current local time as well as at least one other time zone. The additional time element may come from a twin dial, extra hand, subdial, or other means.
E
Elapsed Time Rotating Bezel: A graduated rotating bezel (see "rotating bezel") used to keep track of periods of time. The bezel can be turned so the wearer can align the zero on the bezel with the watch's seconds or minutes hand. You can then read the elapsed time off of the bezel. This saves from having to perform the subtraction that would be necessary if you used the watch's regular dial.
Elapsed Time: The actual time taken for an object to travel over a specified distance.
Engine Turning: engraving, usually on a watch dial.
Escapement: Mechanism made up of the escapement wheel, lever, and discharging roller, which act to control the wheel movement and to provide pulses to pallets and thus the balance. The most important part of the watch. Converts the energy of the mainspring into equal units of time. The escapement controls the amount of power released from the mainspring. The regularity is controlled by the balance and it's spring. The escapement controls the rotation of the wheels and thus the motion of the hands. It is fitted at the end of the gear train and is designed to interrupt the movement of the wheels at regular intervals.
Exhibition Back: Same as a "skeleton" or "display" back.
F
Face: The visible side of the watch or the dial.
Flyback: A seconds hand on a chronograph that can be used to time laps or to determine finishing times for several competitors in a race. Start the chronograph, putting both the flyback hand and the regular chronograph seconds hand in motion. To record a lap time or finishing time, stop the flyback hand. After recording the time, push a button and the hand will "fly back" to catch up with the constantly moving elapsed-time hand. Repeat the process to record as many lap times or finishing times as needed.
G
Grande Complications: The most complex of mechanical watches featuring an abundance of complications. The term is normally restricted to mechanical watches. Quartz watches with additional features are usually described as 'multi-functional'.
H
Hairspring: The (or balance spring) is attached to the balance and cock, and made of metal alloys. Its length determines the amount that the balance regularly oscillates: the shorter the spring the faster the watch runs. It returns the balance wheel back to a neutral position.
Hallmark: A mark stamped into the case of the watch to provide information about the degree of purity of the metal used, the country of origin, the year of manufacturer, the identity of the case's maker, trademarks, reference numbers, and/or serial numbers.
Hand: Watches generally have three hands for seconds, minutes, and hours. They come in many different shapes: Pear, Breguet, Baton, Arrow, Skeleton, Luminous, Alpha, Dauphine and more.
Hand Wound Watch: A watch that receives energy by hand winding the crown.
Hardback: A solid metal caseback.
Horns: Part of the case where the bracelet is attached by lugs or pins.
Horology: Science of time measurement, including the art of designing and constructing timepieces.
J
Jewels: Synthetic sapphires or rubies that are used in a watch movement to reduce friction. They help maintain the watch's lubrication.
L
Lap Timer: A chronograph function that times segments of a race. At the end of a lap a push button stops the time and then returns to zero to time the next lap.
Lug: (same as horn) part of case where bracelet or strap is attached.
Luminous Paint: Self-illuminating paint that is put on the hands and markers to read the time in low light situations.
M
Manual Winding: Refers to a watch with a manual mechanical movement, which needs to be wound by the wearer using the winding crown. This winds the mainspring up which then releases its energy to power the watch.
Mechanical Movement: A movement based on a mainspring which when wound slowly unwinds the spring in an even motion to provide accurate timekeeping. As opposed to a manual mechanical watch which needs to be wound on a consistent basis, an automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist.
Military or 24 Hour Time: When time is measured in 24-hour segments. To convert 12-hour time to 24-hour time, simply add 12 to any p.m. time. To convert 24-hour time to 12-hour time, subtract 12 from any time from 13 to 24.
Mineral Crystal: Watch crystal made from what is essentially a form of glass. More scratch resistant than acrylic, a mineral crystal will however scratch and is extremely difficult to polish.
Minute Repeater: function on a watch that can strike the time in hours, quarters, or seconds by means of a push piece. An extremely complicated function.
Moon Phase: An indicator that keeps track of the phases of the moon. A regular rotation of the moon is once around the earth every 29 days, 12 hours and 44 minutes. Once set, the moon phase indicator accurately displays the phase of the moon.
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 means by which a watch keeps time, often including the power source. For example, a watch with mechanical movement uses a spinning balance wheel powered by a tightly wound spring, whereas a watch with quartz movement measures the vibrations in a piece of quartz and often is powered by a battery.
N
Non Screw Locked Crown: Easier to set than a screw locked crown, but it is less water resistant.
O
Oscillating System: Hairspring and balance form the oscillating system. Two vibrations of the balance make the tick-tack sound of a mechanical watch known as oscillation. The travel of the balance wheel from one extreme to the other and back again.
O-Ring: O-rings are used to seal the backs of watches, which feature either a press-in back or a screw on back. They ensure water resistance. Usually also used on the winding stems of watches and in the winding crowns to protect against the ingestion of water and dust. Normally made from a rubber/plastic compound.
P
Perpetual Calendar: Extremely elaborate complication that keeps track of the day, month, date, and sometimes even the moon phase, zodiac signs, decade, century, and which adjusts for the length of the month and for leap years. (Accurate until 2100).
Pinion: Toothed wheel usually made of steel with a small number of teeth.
Platinum: One of the most rare 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 Indicator: A sub dial used to show how much power remains before the watch stops.
PVD (Physical Vapor Deposition): Method of coating watch cases by integrating titanium particles and then depositing gold for color. Generally comes in black finish, but other colors can be created. (Very similar to "titanium carbide".)
Pulsimeter: A scale on a chronograph watch for measuring the pulse rate.
Push-Piece: Button that is pressed to work a mechanism. Push-pieces are usually found on chronographs, striking watches, and alarms.
Q
Quartz: Natural or synthetic silicon dioxide crystal used in quartz analog or solid state digital watches when activated by a battery or solar power, the thin silver of the crystal very predictably vibrates at an extremely high frequency (32,768 times per second) step motor, electric circuit block.
Quick Set Date: Mechanism to set the date directly to avoid having to turn the hands over 24 hours.
R
Rattrapante: Addition of a second hand to measure split times. (Also called split-second chronograph.)
Regulator: The device inside a watch that speeds it up or slows it down to allow the more precise setting of the watch.
Rotor: Part of an automatic watch that winds the mainspring. A flat piece of metal swivels on a pivot with the motion of the wrist. Its rotation continually winds the mainspring of the watch. It turns freely in both directions and uses the force of gravity to wind the mainspring.
Rubies: Ruby is a very hard stone usually synthetic, which prevents the wear of gear train parts. Also called jewels.
S
Sapphire Crystal: Synthetic corundum crystal with a hardness second only to a diamond. Transparent sapphire is used for a scratch proof watch glass. Made of crystallizing aluminum oxide at very high temperatures. Chemically the same as natural sapphire, but colorless. It is hard and brittle so it shatters easier than plexiglass or mineral glass.
Screw-Down Locking Crown: A crown that aids water resistance by sealing the crown to the case of the watch. The seal is achieved by the matching of a threaded pipe on the case with the crown's internal threads and gaskets, while twisting the crown to lock it into place.
Seal: gaskets that seal the joints between parts of the case and keep out the water.
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.
Self-Winding: This term refers to a mechanically powered watch that is wound by the motion of the wearer's arm rather than through turning the winding stem (manual mechanical). In response to this motion, a rotor turns and winds the watch's mainspring. Most automatic watches have up to 36 hours of power reserve. If an automatic watch is not worn for a day or two, it will wind down and need to be wound by hand to get it started again. Click here for automatic watch instructions.
Shock Absorbers: Spring devices in balance wheel bearings that divert shocks away from the fragile pivot to the sturdier parts of the balance staff. The springs allow the balance wheel to return to its original position after shocks.
Shock Resistance: As defined by the U.S. government regulation, a watch's ability to withstand an impact equal to that of being dropped onto a wood floor from a height of three feet.
Signed: Any of various marks indicating the maker of the watch. Can be found on the dial, the crown, the movement, the back plate, the strap or bracelet, and the clasp. Some maker marks evolved over time and in some cases, the presence of an unsigned part (i.e. crown) does not necessarily mean that it is not original to the watch.
Skeleton Dial / Movement: Movement on a watch where the plates have been removed or trimmed so that you can see the gears and other parts.
Split Second Chronograph: A split seconds chronograph or rattrapante (catch up in French) or doppelchrono (double chrono is German) has two seconds hands, the first push starts both hands together, the second push stops one hand while the other continues, and another push allows the stopped hand to catch up with the moving seconds.
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 resembling a precious metal. Stainless steel is often used even on case backs on watches made of other metals and is the metal of choice used to make high quality watchcases and bracelets. It is also hypoallergenic because it doesn't contain nickel.
Stem: The shaft that connects to the movement's winding mechanism, the crown is fitted to the opposite end.
Sterling Silver: A precious metal. Sterling refers to silver that is 92.5 percent pure. The silver fineness should be stamped on the metal, sometimes accompanied by the initials of a designer or country of origin as a hallmark. 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 stop watch function and the timepiece are referred to as a "chronograph".
Strap: A watchband made of cloth, rubber, leather or other non-metal material. Straps come in sizes (widths) which is the measured distance between the lugs.
Sub Dial: small dial used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date.
Swiss Made: Legally protected indication of Swiss origin. Under terms of the Swiss Federal Council ordinance of December 23, 1971, it can apply only to watches with: -Swiss Movement -Assembled in Switzerland -Final inspection must be done in Switzerland
Swiss Movement: In order for a watch to state that it has Swiss Movement it must: -be assembled in Switzerland -be tested in Switzerland -have 50% of the parts from Swiss origin
T
Tachometer: Instrument for measuring speed over a measured distance. A racing car covers 1 mile in 30 seconds. The sweep second hand, when stopped at the end of the mile, would point to the 120 on the tachometer. The average speed in 120mph.
Tidegraph: Tides are the periodic rise and fall of the water of oceans, seas, bays and other bodies of water caused mainly by the gravitational interactions between the Earth, Moon and Sun. Tides rise and fall about every six hours. The tide graph indicates tidal movement based on the Moon's transit over the meridian and the lunitidal interval. (Also called Tide Function)
Time Zone: The world is divided into 24 time zones spaced at intervals of 15 degrees in longitude. The zones start at 0 with Greenwich. Within each time zone, the hour and minute of the day is defined to be the same. Time zones are usually specified by the number of hours they differ from GMT. EST is GMT 5 hours.
Titanium: A metal, gray in color, that is used for watch cases and bracelets. Much stronger and lighter than stainless steel and hypo-allergenic. It is 30% stronger and 50% lighter than steel. It is very resistant to salt water corrosion, making it useful for diver's watches.
Tourbillon: (or whirlwind) Eliminates errors of rate due to earth's gravity of vertical positions. A complex mechanism requiring the highest watch making skills: consists of a mobile carriage carrying all the parts of the escapement. It is a regulating device which corrects for the gravity-caused differences in run time in a mechanical watch. (Shifts of weight)
U
Uni-Directional Bezel: A bezel that rotates only one way. Generally found on diver"s watches because it only moves one way. It is used to count how much air is left in your tank as you would not want your bezel to accidentally go back, because it could be extremely dangerous if you stay under too long.
W
Water Resistance: The ability to withstand splashes of water. Terms such as "water resistant to 50 meters" or "water resistant to 200 meters" indicate that the watch can be worn underwater to various depths. No watch is 100% waterproof.
WorldTimer: different time zones that can display the current time in any part of the world, without adjusting the crown.
Y
Yacht Timer: a countdown timer that sounds warning signals during the countdown to a boat race
