Watch Wiki



ALARM The watch alerts the wearer with sound or vibrations at pre-set time(s).

ALTIMETER A function that provides altitude by responding to changes in barometric pressure, commonly found in pilot watches. Note that inside a pressurized airplane cabin, the altimeter will register as if on land.

ARM WATCH A watch provided with a movement capable of releasing an acoustic sound at the time set. A second crown is dedicated to the winding, setting and release of the striking-work; an additional center hand indicates the time set. The section of the movement dedicated to the alarm device is made up by a series of wheels linked with the barrel, an escapement and a hammer (s.) striking a gong (s.) or bell (s.). Works much like a normal alarm clock.

ANALOG or ANALOGUE A watch displaying time indications by means of hour and minute hands.

ANALOG-DIGITAL DISPLAY A watch that shows the time by means of hour and minute hands (analog display) as well as by numbers (a digital display).

ANALOG QUARTZ The most commonly-used term in referring to any analog timepiece that operates on a battery or on solar power and is regulated by a quartz crystal.

ANTIMAGNETIC Said of a watch whose movement is not influenced by electromagnetic fields that could cause two or more windings of the balance-spring to stick to each other, consequently accelerating the rate of the watch. This effect is obtained by adopting metal alloys (e.g. Nivarox) resisting magnetization.

ANTIREFLECTION, ANTIREFLECTIVE Superficial glass treatment assuring the dispersion of reflected light. Better results are obtained if both sides are treated, but in order to avoid scratches on the upper layer, the treatment of the inner surface is preferred.

ARBOR Bearing element of a gear (s.) or balance, whose ends called pivots (s.) run in jewel (s.) holes or brass bushings.

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 A watch whose mechanical movement (s.) is wound automatically. A rotor makes short oscillations due to the movements of the wrist. Through a series of gears, oscillations transmit motion to the barrel (s.), thus winding the mainspring progressively.

AUTOMATON Figures, placed on the dial or case of watches, provided with parts of the body or other elements moving at the same time as the sonnerie (s.) strikes. The moving parts are linked, through an aperture on the dial or caseback, with the sonnerie hammers (s.) striking a gong.



BAGUETTE Ladies style watch with a thin, elongated face; usually rectangular in shape but may be oval.

BALANCE Oscillating device that, together with the balance spring (s.), makes up the movements heart inasmuch as its oscillations determine the frequency of its functioning and precision.

BALANCE SPRING Component of the regulating organ (s.) that, together with the balance (s.), determines the movements precision. The material used is mostly a steel alloy (e.g. Nivarox, s.), an extremely stable metal compound. In order to prevent the systems center of gravity from continuous shifts, hence differences in rate due to the watches position, some modifications were adopted. These modifications included Breguets overcoil (closing the terminal part of the spring partly on itself, so as to assure an almost perfect centering) and Philips curve (helping to eliminate the lateral pressure of the balance-staff pivots against their bearings). Today, thanks to the quality of materials, it is possible to assure an excellent precision of movement working even with a flat spring.

BANGLE BRACELET A type of bracelet found on some ladies watches that are of fixed size and rigid.

BARREL Component of the movement containing the mainspring (s.), whose toothed rim meshes with the pinion of the first gear of the train (s.). Due to the fact that the whole made up of barrel and mainspring transmits the motive force, it is also considered to be the very motor. Inside the barrel, the mainspring is wound around an arbor (s.) turned by the winding crown or, in the case of automatic movements, also by the gear powered by the rotor (s.).

BASE METAL Any non-precious metal.

BATTERY 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 volt.

BATTERY LIFE The minimum period of time that a battery will continue to provide power to run the watch. Life begins at the point of manufacture when the factory initially installs the battery.

BATTERY RESERVE INDICATOR Some battery-operated watches have a feature that indicates when the battery is approaching the end of its life. This is often indicated by the second hand moving in two second intervals instead of each second.

BEVELING Chamfering of edges of levers, bridges and other elements of a movement by 45, a treatment typically found in high-grade movements.

BEZEL Top part of case (s.), sometimes holds the crystal. It may be integrated with the case middle (s.) or a separate element. It is snapped or screwed on to the middle.

BI-DIRECTIONAL ROTATING BEZEL A bezel that can be rotated either clockwise or counterclockwise. These are used for mathematical calculations such as average speed or distance or for keeping track of elapsed time.

BRACELET A metal band attached to the case. It is called integral if there is no apparent discontinuity between case and bracelet and the profile of attachments is similar to the first link.

BRASS Copper and zinc alloy used to make the main plate and bridge wheels in the movement.

BRIDGE Structural metal element of a movement (s.) sometimes called cock or bar supporting the wheel train (s.), balance (s.), escapement (s.) and barrel (s.). Each bridge is fastened to the plate (s.) by means of screws and locked in a specific position by pins. In high-quality movements the sight surface is finished with various types of decoration.

BRUSHED, BRUSHING Topical finishing giving metals a line finish, a clean and uniform look. top

BUCKLE Usually matching the case, it attaches the two parts of the leather strap around the wrist.

BUILT-IN ILLUMINATION Lighting on a watch dial that allows the wearer to read the time in the dark.

BUTTON Push piece controls, usually at 2 o'clock and/or 4 o'clock on the dial to control special functions such as the chronograph or the alarm.



CABOCHON Any kind of precious stone, such as sapphire, ruby or emerald, uncut and only polished, generally of a half-spherical shape, mainly used as an ornament of the winding crown (s.) or certain elements of the case.

CALENDAR, ANNUAL An intermediate complication between a simple calendar and a perpetual calendar. This feature displays all the months with 30 or 31 days correctly, but needs a manual correction at the end of February. Generally, date, day of the week and month, or only day and month are displayed on the dial.

CALENDAR, FULL Displaying date, day of the week and month on the dial, but needing a manual correction at the end of a month with less than 31 days. It is often combined with the moonphase (s).

CALENDAR, PERPETUAL This is the most complex horology complication related to the calendar feature, as it indicates the date, day, month and leap year and does not need manual corrections until the year 2100 (when the leap year will be ignored).

CALIBER Originally it indicated only the size of a movement (s.), but now this indication defines a specific movement type and shape (e.g. round caliber) and combines it with the constructors name and identification number. Therefore the caliber identifies the movement.

CARAT (KARAT) Unit of gold fineness (and gemstone weight). Pure gold is 24k. 18k gold is 75% pure.

CARRIAGE or TOURBILLON CARRIAGE Rotating frame of a tourbillon (s.) device, carrying the balance and escapement (s.). This structural element is essential for a perfect balance of the whole system and its stability, in spite of its reduced weight. As todays tourbillon carriages make a rotation per minute, errors of rate in the vertical position are eliminated. Because of the widespread use of transparent dials, carriages became elements of aesthetic attractiveness.

CASE Container housing and protecting the movement (s.), usually made up of three parts: middle, bezel, and back.

CENTER SECOND HAND, s. Sweep second hand.

CHAMPLEVÉ Hand-made treatment of the dial or case surface. The pattern is obtained by hollowing a metal sheet with a graver and subsequently filling the hollows with enamel.

CHRONOGRAPH A watch that includes a built-in stopwatch function, i.e. a timer that can be started and stopped to time an event. There are many variations of the chronograph.

CHRONOMETER A high-precision watch. According to the Swiss law, a manufacture may put the word chronometer on a model only after each individual piece has passed a series of tests and obtained a running bulletin and a chronometer certificate by an acknowledged Swiss control authority, such as the COSC(s.).

CIRCULAR GRAINING Superficial decoration applied to bridges, rotors and pillar-plates in the shape of numerous slightly superposed small grains, obtained by using a plain cutter and abrasives. Also called Pearlage or Pearling.

CLASP The attachment used to connect the two ends of the watch bracelet or strap around the wrist.
1. Deployment Buckle - A three-folding enclosure, which 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.
2. Hook Lock - Two separate units each fitting on either end of the bracelet which allows the watch to be laid out. One end of the closure hooks onto the other to secure the two ends of the bracelet.
3. Jeweler's Clasp - A closure that is generally used on better bracelets. Also allows it to lie flat.
4. Sliding Clasp - Also a hook type method but allows for easy sizing of the bracelet by sliding up.
5. Twist Lock - A closure similar to Jeweler's Clasp used on ladies jewelry bracelets.

CLOISONNÉ A kind of enamel work€” mainly used for the decoration of dials€”in which the outlines of the drawing are formed by thin metal wires. The colored enamel fills the hollows formed in this way. After oven firing, the surface is smoothed until the gold threads appear again.

CLOUS DE PARIS Decoration of metal parts characterized by numerous small pyramids.

COCK, s. Bridge.


COLUMN-WHEEL Part of chronograph movements, governing the functions of various levers and parts of the chronograph operation, in the shape of a small-toothed steel cylinder. It is controlled by pushers through levers that hold and release it. It is a very precise and usually preferred type of chronograph operation.

COMPLICATION Additional function with respect to the manual-winding basic movement for the display of hours, minutes and seconds. Today, certain features, such as automatic winding or date, are taken for granted, although they should be defined as complications. The main complications are moonphase (s.), power reserve (s.), GMT (s.), and full calendar (s.). Further functions are performed by the so-called great complications, such as split-second (s.) chronograph, perpetual calendar (s.), tourbilon (s.) device, and minute repeater (s.).

CORRECTOR Pusher (s.) positioned on the case side that is normally actuated by a special tool for the quick setting of different indications, such as date, GMT (s.), full or perpetual calendar (s.).

COSC Abbreviation of €œContrôle Officiel Suisse des Chronomètres,€ the most important Swiss institution responsible for the functioning and precision tests of movements of chronometers (s.). Tests are performed on each individual watch at different temperatures and in different positions before a functioning bulletin and a chronometer certificate are issued, for which a maximum gap of -4/+4 seconds per day is tolerated.

CÔTES CIRCULAIRES Decoration of rotors and bridges of movements, whose pattern consists of a series of concentric ribs.

CÔTES DE GENÈVE Decoration applied mainly to high-quality movements, appearing as a series of parallel ribs, realized by repeated cuts of a cutter leaving thin stripes.

COUNTDOWN TIMER A function that lets the wearer keep track of how much of a pre-set period of time has elapsed. Some countdown timers sound a warning signal a few seconds before the time runs out. These are useful in events such all kinds of race.

COUNTER Additional hand on a chronograph (s.), indicating the time elapsed since the beginning of the measuring. On modern watches the second counter is placed at the center, while minute and hour counters have off-center hands in special zones (s.), also called subdials.

CROWN Usually positioned on the case middle (s.) and allows winding, hand setting and often date or GMT hand setting. As it is linked to the movement through the winding stem (s.) passing through a hole in the case. For waterproofing purposes, simple gaskets are used in water-resistant watches, while diving watches adopt screwing systems (screw-down crowns).

CRYSTAL The clean cover over the watch face. Three types of crystals are commonly found in watches. Acrylic crystal, a plastic, is inexpensive and shallow scratches can be buffed out. Mineral crystal is comprised of several elements that are heat treated to create unusual hardness that aids in resisting scratches. Sapphire crystal is the most expensive and durable, approximately three times harder than mineral crystals and 20 time harder than acrylic crystals. A non-reflective coating on some sport styles prevents glare.



DEPTH ALARM An alarm on a divers' watch that sounds when the wearer exceeds a pre-set depth.

DEPTH SENSOR/DEPTH METER A device on a divers' watch that determines the wearer's depth by measuring water pressure. It shows the depth either by analog hands and a scale on the watch face or through a digital display.

DIAL Face of a watch, on which time and further functions are displayed by markers (s.), hands (s.), discs or through windows (s.). Normally it is made of a brass sometimes silver or gold.

DIGITAL WATCH Said of watches whose indications are displayed mostly inside an aperture or window (s.) on the dial.

DIVERS WATCH A watch that is water resistant to 200M. Has a one way rotating bezel and a screw-on crown and back. Has a metal or rubber strap (not leather). Has a sapphire crystal and possibly, a wet-suit extension.



ECO-DRIVE A name for a patented power mechanism found on some Citizen watches. This mechanism uses ordinary light to keep a rechargeable battery powered for watch operation. This technology is very sophisticated allowing some watch models to remain powered for up to 5 years in the dark. Watches with Eco-Drive technology will never need to have the battery replaced.

ELAPSED TIME ROTATING BEZEL A graduated rotating bezel used to keep track of elapsed time. The bezel can be turned so the wearer can align the zero on the bezel with the watch's seconds or minutes hand. After a period of time passes, you can read the elapsed time off the bezel. This saves you having to perform the subtraction that would be necessary if you used the watch's regular dial.

ELECTROPLATING PROCESS Process of covering metal articles with a film of other metals. The article is immersed in a chemical solution; electric current (D.C.) flows through the solution from a piece of metal (anode) to the article (cathode), depositing metal thereon by electrolysis.

ENDSTONE Undrilled jewel, placed on the balance jewel with the tip of the balance-staff pivot resting against its flat surface, to reduce pivot friction. Sometimes used also for pallet staffs and escape wheels.

ENGINE-TURNED, s. Guillochà .

EQUATION OF TIME Indication of the difference, expressed in minutes, between conventional mean time and real solar time. This difference varies from -16 to +16 seconds between one day and the other.

ESCAPEMENT Positioned between the train (s.) and the balance wheel and governing the rotation speed of the wheel-train wheels. In todays horology the most widespread escapement type is the lever escapement. In the past, numerous types of escapements were realized, such as: verge, cylinder, pin-pallet, detent and duplex escapements. Recently, George Daniels developed a so-called €œcoaxial€ escapement.



FLINQUÉ Engraving on the dial or case of a watch, covered with an enamel layer.

FLUTED Said of surfaces worked with thin parallel grooves, mostly on dials or case bezels.

FLY-BACK Feature combined with chronograph (s.) functions, that allows a new measurement starting from zero (and interrupting a measuring already under way) by pressing down a single pusher, i.e. without stopping, zeroing and restarting the whole mechanism. Originally, this function was developed to meet the needs of air forces.

FOLD-OVER CLASP Hinged and jointed element, normally of the same material as the one used for the case. It allows easy fastening of the bracelet on the wrist. Often provided with a snap-in locking device, sometimes with an additional clip or push-piece.

FREQUENCY, s. Vibration Generally defined as the number of cycles per time unit; in horology it is the number of oscillations of a balance every two seconds or of its vibrations per second. For practical purposes, frequency is expressed in vibrations per hour (vph).



GENEVA SEAL, s. Poinçon de Genève.

GLASS (CRYSTAL) Thin plate of glass or transparent synthetic material, for protecting the dials of watches, clocks, etc.

GLUCYDUR Bronze and beryllium alloy used for high-quality balances (s.). This alloy assures high elasticity and hardness values; it is non-magnetic, rustproof and has a very reduced dilatation coefficient, which makes the balance very stable and assures high accuracy of the movement.

GMT Abbreviation for Greenwich Mean Time. As a feature of watches, it means that two or more time zones are displayed. In this case, the second time may be read from a hand making a full rotation in a 24-hour ring (thereby also indicating whether it is a.m. or p.m. in that zone).

GOLD Yellow precious metal which is stainless and very malleable. Used in alloys to make jewelry, bracelets and watches. The portion of gold in the alloy is indicated in carats (k).

GOLD PLATED A layer of gold electroplated to a base metal.

GONG Harmonic flattened bell in a steel alloy, generally positioned along the circumference of the movement and struck by hammers (s.) to indicate time by sounds. Size and thickness determine the resulting note and tone. In watches provided with minute-repeaters (s.), there are often two gongs and the hammers strike one note to indicate hours, both notes together to indicate quarters and the other note for the remaining minutes. In more complex models, equipped also with en-passant sonnerie (s.) devices, there may be up to four gongs producing different notes and playing even simple melodies (such as the chime of London€™s Big Ben).

GUILLOCHà © Decoration of dials, rotors or case parts consisting of patterns made by hand or engine-turned. By the thin pattern of the resulting engravings€”consisting of crossing or interlaced lines€”it is possible to realize even complex drawings. Dials and rotors decorated in this way are generally in gold or in solid silver.



HAMMER Steel or brass element used in movements provided with a repeater or alarm sonnerie (s.). It strikes a gong (s.) or bell (s).

HAND Indicator for the analogue visualization of hours, minutes and seconds as well as other functions. Normally made of brass (rhodium-plated, gilded or treated otherwise), but also steel or gold. Hands are available in different shapes and take part in the aesthetic result of the whole watch.

HARDLEX CRYSTAL is Seiko's trademarked name for a hardened mineral crystal (s.).

HEART-PIECE Heart-shaped cam (s.) generally used to realign the hands of chronograph counters.

HELIUM VALVE Valve inserted in the case of some professional diving watches to discharge the helium contained in the air mixture inhaled by divers.

HESALITE Back in the 1960's, many watches used either mineral glass or acrylic (plastic) crystals. These are not difficult to scratch, but very inexpensive to replace. Now though, most all luxury watches use the highly scratch resistant synthetic sapphire crystals, there are some styles/brands that use the Hesalite (a name brand of fine acrylic) crystal. The reason for this is directly related to the watch's certification for use in space or in high stress/impact situations. While sapphire crystals are less prone to scratching, they can be shattered. When shattered, they break into tiny fragments that would be hazardous in some environments. So the Hesalite crystal is maintained on some specific models as a safety feature.

HEXALITE An artificial glass made of a plastic resin. See Hesalite.



INCABLOC, s. Shockproof.



JEWEL Precious stone used in movements as a bearing surface. Generally speaking, the steel pivots (s.) of wheels in movements turn inside synthetic jewels (mostly rubies) lubricated with a drop of oil. The jewel€™s hardness reduces wear to a minimum even over long periods of time (50 to 100 years). The quality of watches is determined mainly by the shape and finishing of jewels rather than by their number (the most refined jewels have rounded holes and walls to greatly reduce the contact between pivot and stone).

JUMPING HOUR Feature concerning the digital display of time in a window. The indication changes almost instantaneously at every hour.



KINETIC Refers to the Seiko line of Kinetic watches. This innovative technology has a quartz movement that does not use a battery. Movement of the wrist charges a very efficient capacitor which powers the quartz movement. Once the capacitor is fully charged, men's models will store energy for 7-14 days without being worn. Ladies models store energy for 3-7 days. Of course, if the watch is worn every day the capacitor is continually recharged. The watch alerts the owner to a low capacitor charge when the seconds hand starts to move in two second intervals. Some of Seiko's Kinetic Watches have See-Thru CaseBacks, that use a clear, Hardlex (Mineral Crystal) watch back to enable the wearer to view the kinetic movement.

KINETIC AUTO RELAY A Seiko Kinetic Auto Relay watch is also powered by human movement, however when it senses inactivity for three days, it puts itself into suspended animation to conserve energy. It can be re-activated with a few shakes of the wrist. It automatically resets itself to the exact time after to up to four years of dormancy.



LAP TIMER A chronograph function that lets the wearer time segments of a race. At the end of a lap, he stops the timer, which then returns to zero to begin timing the next lap.

LINE Ancient French measuring unit maintained in horology to indicate the diameter of a movement (s.). A line (expressed by the symbol) equals 2.255mm. Lines are not divided into decimals; therefore, to indicate measures inferior to the unit, fractions are used (e.g. movements of 133/4 or 101/2).

LIQUID CRYSTAL DISPLAY (LCD) A digital watch display that shows the time electronically by means of a liquid held in a thin layer between two transparent plates. All LCD watches have quartz movements.

LUBRICATION To reduce friction caused by the running of wheels and other parts. There are points to be lubricated with specific low-density oils such as the pivots (s.) turning inside jewels (s.), the sliding areas between levers, and the spring inside the barrel (requiring a special grease), as well as numerous other parts of a movement.

LUG Double extension of the case middle (s.) by which a strap or bracelet is attached. Normally, straps and bracelets are attached with removable spring bars.

LUMIBRITE LumiBrite watches from are environmentally safe and will glow brightly for hours without pushing a button or drawing energy from a battery.

LUMINESCENT or LUMINOUS Said of materials applied on markers (s.) and/or hands (s.), emitting the luminous energy previously absorbed as electromagnetic light rays. Tritium is no longer used and was replaced by other substances having the same emitting powers, but with virtually zero radioactivity, such as Super-LumiNova and Lumibrite (s).



MAINSPRING This and the barrel (s.) make up the driving element of a movement (s.). It stores and transmits the power force needed for its functioning.

MANUAL A mechanical movement (v.) in which winding is performed by hand. The motion transmitted from the user's fingers to the crown is forwarded to the movement through the winding stem (s.), from this to the barrel (s.) through a series of gears (s.) and finally to the mainspring (s.).

MARKERS Elements printed or applied on the dial, sometimes they are luminescent (s.), used as reference points for the hands to indicate hours and fifteen- or five-minute intervals.

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 powered by a mainspring, working in conjunction with a balance wheel. Most watches today have electronically controlled quartz movements and are powered by a battery. However, mechanical watches are currently enjoying a resurgence in popularity.

MICROMETER SCREW Element positioned on the regulator, allowing to shift it by minimal and perfectly gauged ranges so as to obtain accurate regulations of the movement.

MICRO-ROTOR, s. Rotor.

MILITARY OR 24-HOUR TIME When time is 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.

MINERAL GLASS OR MINERAL CRYSTAL Watch glass that has been tempered to increase its scratch resistance.


MODULE Self-contained mechanism, independent of the basic caliber (s.), added to the movement (s.) to make an additional function available: chronograph (s.), power reserve (s.), GMT (s.), perpetual or full calendar (s).

MOONPHASE A function available in many watches, usually combined with calendar-related features. The moonphase disc advances one tooth every 24 hours. Normally, this wheel has 59 teeth and assures an almost perfect synchronization with the lunation period, i.e. 29.53 days (in fact, the disc shows the moonphases twice during a single revolution). However, the difference of 0.03 days, i.e. 44 minutes each month, implies the need for a manual adjustment every two and a half years to recover one day lost with respect to the real state of moonphase. In some rare case, the transmission ratio between the gears controlling the moonphase are calculated with extreme accuracy so as to require manual correction only once in 100 years.

MOTHER OF PEARL 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.

MOVEMENT The entire mechanism of a watch. Movements are divided into two great families: quartz and mechanical; the latter are available with manual (s.) or automatic (s.) winding devices.



NIVAROX Trade name (from the producer's name) of a steel alloy, resisting magnetization, used for modern self-compensating balance springs (s.). The quality level of this material is indicated by the numeral following the name in decreasing value from 1 to 5.



OSCILLATION Complete oscillation or rotation movement of the balance (s.), formed by two vibrations (s.).



PALLETS Device of the escapement (s.) transmitting part of the motive force to the balance (s.), in order to maintain the amplitude of oscillations unchanged by freeing a tooth of the escape wheel at one time.

PERPETUAL CALENDAR A type of calendar that automatically adjusts for months of different lengths and indicates February 29 in each leap year.

PILLAR-PLATE or MAIN PLATE Supporting element of bridges (s.) and other parts of a movement (s).

PINION Combines with a wheel and an arbor (s.) to form a gear (s.). A pinion has less teeth than a wheel and transmits motive force to a wheel. Pinion teeth (normally 6 to 14) are highly polished to reduce friction to a minimum.

PIVOT End of an arbor (s.) turning on a jewel (s.) support. As their shape and size can influence friction, the pivots of the balance-staff are particularly thin and, hence, fragile, so they are protected by a shockproof (s.) system.

PLATED Said of a metal treated by a galvanizing procedure in order to apply a slight layer of gold or another precious metal (silver, chromium, rhodium or palladium) on a brass or steel base.

PLATINUM 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. 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.

PLEXIGLAS A synthetic resin used for watch crystal.

POINÇON DE GENÈVE Distinction assigned by the Canton of Geneva to movements produced by watchmaker firms of the Region and complying with all the standards of high horology with respect to craftsmanship, small-scale production, working quality, accurate assembly and setting. The Geneva Seal is engraved on at least one bridge and shows the Cantons symbol, i.e. a two-field shield with an eagle and a key respectively in each field.

POLISHED FINISH Brilliant metal surface obtained on the watch-case with fine abrasive. Compare to brushed finish (s.).

POWER RESERVE Duration (in hours) of the residual functioning autonomy of a movement after it has reached the winding peak. The duration value is displayed by an instantaneous indicator: analog (hand on a sector) or digital (through a window). The related mechanism is made up of a series of gears linking the winding barrel and hand. Recently, specific modules were introduced which may be combined with the most popular movements.

PULSIMETER CHRONOGRAPH The pulsimeter scale shows, at a glance, the number of pulse beats per minute. The observer releases the chronograph hand when starting to count the beats and stops at the 30th, the 20th or the 15th beat according to the basis of calibration indicated on the dial.

PUSHER, PUSH-PIECE or PUSH-BUTTON Mechanical element mounted on a case (s.) for the control of specific functions. Generally, pushers are used in chronographs (s.), but also with other functions.

PVD Abbreviation of Physical Vapor Deposition, a plating process consisting of the physical transfer of substance by bombardment of electrons.



QUARTZ MOVEMENTM A movement powered by a quartz crystal. Quartz crystals are very accurate. They can be mass produced which makes them less expensive than most mechanical movements which require a higher degree craftsmanship.



REGULATING UNIT Made up by balance (s.) and balance spring (s.), governing the division of time within the mechanical movement, assuring its regular running and accuracy. As the balance works like a pendulum, the balance springs function consists of its elastic return and starting of a new oscillation. This combined action determines the frequency, i.e. the number of vibrations per hour, and affects the rotation speed of the different wheels. In fact the balance, by its oscillations, at every vibration (through the action of the pallets), frees a tooth of the escape wheel (s. Escapement). From this, motion is transmitted to the fourth wheel, which makes a revolution in one minute, to the third and then the center wheel, the latter making a full rotation in one hour. However, everything is determined by the correct time interval of the oscillations of the balance.

REGULATOR Regulating the functioning of a movement by lengthening and shortening the active section of the balance spring (s.). It is positioned on the balance-bridge and encompasses the balance spring with its two pins near its fixing point on the bridge itself. By shifting the index, the pins also are moved and, by consequence, the portion of the balance spring capable of bringing the balance back is lengthened or shortened by its elastic force. The shorter it is, the more reactive it tends to be and the more rapidly it brings the balance back and makes the movement run faster. The contrary happens when the active portion of the balance spring is lengthened. Given today€™s high frequencies of functioning, even slight index shifts entail daily variations of minutes. Recently, even more refined index-regulation systems were adopted (from eccentric (s.) to micrometer screws (s.)) to limit error margins to very few seconds per day.

REPEATER Mechanism indicating time by acoustic sounds. Contrary to the watches provided with en-passant sonnerie (s.) devices, that strike the number of hours automatically, repeaters work on demand by actuating a slide (s.) or pusher (s.) positioned on the case side. Repeaters are normally provided with two hammers and two gongs: one gong for the minutes and one for the hours. The quarters are obtained by the almost simultaneous strike of both hammers. The mechanism of the striking work is among the most complex complications.

RETROGRADE Said of a hand (s.) that, instead of making a revolution of 360 before starting a new measurement, moves on an arc scale (generally of 90 to 180) and at the end of its trip comes back instantaneously. Normally, retrograde hands are used to indicate date, day or month in perpetual calendars, but there are also cases of retrograde hours, minutes or seconds. Unlike the case of the classical indication over 360, the retrograde system requires a special mechanism to be inserted into the basic movement.

ROTATING BEZEL A bezel (the ring surrounding the watch face) that can be turned. Different types of rotating bezels perform different time keeping and mathematical functions.

ROTOR In automatic-winding mechanical movements the rotor is the part that, by its complete or partial revolutions and the movements of human arm, allows winding of the mainspring (s.).



SAPPHIRE CRYSTAL Synthetic corundum crystal with a hardness second only to diamond. Transparent sapphire is used for scratch-proof watch glasses.

SAPPHLEX CRYSTAL Seiko's trademarked name for a fusion of Sapphire and Mineral (s.) Glass Crystals (s.)

SCALE Graduation on a measuring instrument, showing the divisions of a whole of values, especially on a dial, bezel. The scales mostly used in horology are related to the following measuring devices: tachometer (s.) (indicating the average speed), telemeter (s.) (indicating the distance of a simultaneously luminous and acoustic source, e.g. a cannon-shot or a thunder and related lightning), pulsometer (to calculate the total number of heartbeats per minute by counting only a certain quantity of them). For all of these scales, measuring starts at the beginning of the event concerned and stops at its end; the reading refers directly to the chronograph second hand, without requiring further calculations.

SCREW-DOWN LOCKING CROWN A crown which aids water resistance by sealing the crown against the case. The seal is achieved by the matching of a threaded pipe on the case with the crown's internal threads and gasketing while twisting the crown to lock it into place.

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. s. GMT and World Time.

SECTOR, s. Rotor.

SELF-WINDING, s. Automatic.

SHOCKPROOF or SHOCK-RESISTANT Watches provided with shock-absorber systems (e.g. Incabloc) help prevent damage from shocks to the balance pivots. Thanks to a retaining spring system, it assures an elastic play of both jewels, thus absorbing the movements of the balance-staff pivots when the watch receives strong shocks. The return to the previous position is due to the return effect of the spring. If such a system is lacking, the shock forces exert an impact on the balance-staff pivots, often causing bending or even breakage. As defined by 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 3 feet.

SKELETON or SKELETONIZED Watches whose bridges and pillar-plates are cut out in a decorative manner, thus revealing all the parts of the movement.

SLIDE Part of a mechanism moving with friction on a slide-bar or guide.

SLIDE RULE A device, consisting of logarithmic or other scales on the outer edge of the watch face, that can be used to do mathematical calculations. One of the scales is marked on a rotating bezel, which can be slid against the stationary scale to make the calculations. Some watches have slide rules that allow specific calculations, such as for fuel consumption by an airplane or fuel weight.

SMALL SECOND Time display in which the second hand is placed in a small subdial.

SNAILING Decoration with a spiral pattern, mainly used on the barrel wheel or on big-sized full wheels.

SOLAR POWERED A watch that uses solar energy (from any light source) to power the quartz movement. Citizen call their solar powered watches "Eco-Drive" (s.).

SONNERIE (EN PASSANT) Function consisting of an acoustic sound, obtained by a striking work made up of two hammers (s.) striking gongs (s.) at set hours, quarter- and half-hours. Some devices can emit a chime (with three or even four hammers and gongs). By a slide (s.) or an additional pusher (s.) it is possible to exclude the sonnerie device and to select a so-called grande sonnerie.

SPLIT-SECOND CHRONOGRAPH Chronographs with split-second mechanisms are particularly useful for timing simultaneous phenomena which begin at the same time, but end at different times, such as sporting events in which several competitors are taking part. In chronographs of this type, an additional hand is superimposed on the chronograph hand. Pressure on the pusher starts both hands, which remain superimposed as long as the split-second mechanism is not blocked. This is achieved when the split-second hand is stopped while the chronograph hand continues to move. After recording, the same pusher is pressed a second time, releasing the split-second hand, which instantly joins the still-moving chronograph hand, synchronizing with it, and is thus ready for another recording. Pressure on the return pusher brings the hands back to zero simultaneously, provided the split-second hand is not blocked. Pressure on the split pusher releases the split-second hand, which instantly joins the chronograph hand if the split-second hand happens to be blocked.

STAFF or STEM, s. Arbor.

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.

STRAP A watch band made of leather, plastic or fabric.

STRIKING WORK, s. Sonnerie and Repeater.

SUB-DIAL A small dial on a watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date. s. Zone.

SUPER-LUMINOVA, s. Luminescent.

SWEEP SECOND HAND A center second hand, i.e. a second hand mounted on the center of the main dial.



TACHOMETER or TACHYMETER Function measuring the speed at which the wearer runs over a given distance. The tachometer scale is calibrated to show the speed of a moving object, such as a vehicle, over a known distance. The standard length on which the calibration is based is always shown on the dial, e.g. 1,000, 200 or 100 meters, or in some cases€”one mile. As the moving vehicle, for instance, passes the starting-point of the measured course whose length corresponds to that used as the basis of calibration, the observer releases the chronograph hand and stops it as the vehicle passes the finishing point. The figure indicated by the hand on the tachometer scale represents the speed in kilometers or miles per hour.

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 By means of the telemeter scale, it is possible to measure the distance of a phenomenon that is both visible and audible. The chronograph hand is released at the instant the phenomenon is seen; it is stopped when the sound is heard, and its position on the scale shows, at a glance, the distance in kilometers or miles separating the phenomenon from the observer. Calibration is based upon the speed at which sound travels through the air, viz. approximately 340 meters or 1,115 feet per second. During a thunderstorm, the time that has elapsed between the flash of lightning and the sound of the thunder is registered on the chronograph scale.

TICN PLATING A plating process applied to the cases (s.) and bracelets (s.) of some watches that consists of a titanium (s.), carbon and nitride compound. This process creates lustrous satin and polished finishes in shades of black and grey.

TIMER Instrument used for registering intervals of time (duration, brief times), without any indication of the time of day.

TITANIUM Titanium is an environmentally friendly, natural metal that is 40% stronger and 30% lighter than stainless steel. It is hypoallergenic because it is nickel-free. It is perfect for water sport enthusiasts as it is extremely resistant to salt water and other forms of corrosion and able to withstand extreme temperatures. Many titanium watches are further enhanced with a glass coating for increased scratch resistance.

TONNEAU Particular shape of a watchcase, imitating the profile of a barrel, i.e. with straight, shorter, horizontal sides and curved, longer, vertical sides.

TOURBILLON Device invented in 1801 by A. L. Breguet. This function equalizes position errors due to changing positions of a watch and related effects of gravity. Balance, balance spring and escapement are housed inside a carriage (s.), also called a cage, rotating by one revolution per minute, thus compensating for all the possible errors over 360. Although this device is not absolutely necessary for accuracy purposes today, it is still appreciated as a complication of high-quality watches.

TWO-TONE A term use to indicate that a watch has both "silver" and "gold" tone color which may or may not be genuine gold or silver.



UNIDIRECTIONAL ROTATING BEZEL An elapsed time rotating bezel (see "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 err 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 bodies, limited by two consecutive extreme positions. In an alternate (pendulum or balance) movement, a vibration is a half of an oscillation (s.). The number of hourly vibrations corresponds to the frequency of a watch movement, determined by the mass and diameter of a balance (s.) and the elastic force of the balance spring. The number of vibrations per hour (vph) determines the breaking up of time (the steps of a second hand). For instance, 18,000 vph equals a vibration duration of 1/5 second; in the same way 21,600 vph = 1/6 second; 28,800 vph = 1/8 second; 36,000 vph = 1/10 second. Until the 1950s, wristwatches worked mostly at a frequency of 18,000 vph; later, higher frequencies were adopted to produce a lower percentage of irregularities to the rate. Today, the most common frequency adopted is 28,800 vph, which assures a good precision standard and less lubrication problems than extremely high frequencies, such as 36,000 vph.



WATER RESISTANT or WATERPROOF A watch whose case (s.) is designed in such a way as to resist infiltration by water (3 atmospheres, corresponding to a conventional depth of 30 meters; 5 atmospheres, corresponding to a conventional depth of 50 meters.)

WHEEL Circular element, mostly toothed, combines with an arbor (s.) and a pinion (s.) to make up a gear (s.). Wheels are normally made of brass, while arbors and pinions are made of steel. The wheels between barrel (s.) and escapement (s.) make up the so-called train (s.).

WINDING STEM Element transmitting motion from the crown (s.) to the gears governing manual winding and setting.

WINDOW Aperture in the dial, that allows reading the underlying indication, mainly the date, but also indications concerning a second zones time or jumping hour (s.).

WORLD TIME Additional feature of watches provided with a GMT (s.) function, displaying the 24 time zones on the dial or bezel, each zone referenced by a city name, providing instantaneous reading of the time of any country.



ZONE Small additional dial or indicator that may be positioned, or placed off-center on the main dial, used for the display of various functions (e.g. second counters).