Welcome to the Fine Watches of China Learning Centre. 

In addition to our Glossary of Watch Terms, we have compiled many of the key terms into several “Cook’s Tours” to allow you to obtain further information on specific watchmaking topics. 

The terms have been placed in specific order to allow you to logically step through the list, gaining progressive knowledge as you go.  

Alternatively you can look down the list of terms and selectively pick any terms that you would like a further understanding of.  We hope this can be of assistance to you.

Mechanical watches

Accuracy

Refers to the minimum and maximum expected rate variation of a watch over a 24 hour period. For example a watch with a published accuracy range of -10 to +25 can be expected to lose no more than 10 seconds, nor gain no more than 25 seconds, over a 24 hour period. The narrower this accuracy range, the more accurate the watch. A watch that loses or gains a very 'consistent' amount each day is considered accurate.

Adjustment

An Adjustment, also called a regulation, of a watch refers to the regulation process performed by a watchmaker on a mechanical watch to optimise and 'fine tune' its accuracy. This adjustment process accounts for variations in rate caused by a watch's position and sometimes other factors such as temperature and isochronism. There are various adjustments for position that a watchmaker may use to fine tune mechanical watches, these include crown up, crown down, crown left, crown right, dial up and dial down.

Amplitude

Amplitude is the measure of the amount of rotation or swing of the balance wheel in a mechanical watch, expressed in degrees. The balance consists of a balance wheel that continually oscillates (rotates) backwards and forwards on its axis, each time releasing a small, incremental forward movement of the watch's escapement and gear train. Amplitude is thus the angle of rotation in degrees, of the balance wheel in each direction (clockwise then counter clockwise) away from its central position. In a well-serviced watch, the amplitude should be between approximately 275 and 315 degrees (in either a dial up or dial down position).

Anti-magnetic Watch

Magnetic fields found in typical everyday environments, such as near electronic devices and refrigerator doors, can affect the accuracy or precision of mechanical watch movements. An anti-magnetic watch is a watch that contains components or casing material specifically designed to negate or reduce the effects of these external magnetic fields. For example this includes a watch that contains materials that either cannot be magnetised or are resistant to becoming magnetised.

Arbor

An axle, pinion or pivot point of a wheel or gear component of a watch's movement, upon which the gear rotates.

Balance

The part of a mechanical watch movement that regulates the time. The balance consists of a balance wheel that continually oscillates (rotates) backwards and forwards on its axis, each time releasing a small, incremental forward movement of the watches escapement and gear train. The rate of oscillation is governed by a very fine spring called a balance spring or hairspring. The rate of oscillation is counted in "beats" or "vibrations" per hour (BPH/VPH), commonly 21,600 or 28,800 times per hour. The balance is said to be the "heart-beat" of a mechanical watch.

Balance Cock

A small structural plate in a mechanical movement that is screwed to the base plate at one end, upon which the balance wheel and regulator assemblies are mounted.

Balance Spring (Hairspring)

A very fine, flat coiled spring found in mechanical watch movements that, in conjunction with the balance wheel, regulates its timekeeping. The balance spring is attached to the balance wheel in such as way that its expansion and contraction causes the balance wheel to continuously swing (oscillate) backwards and forwards on its axis (in a clockwise and then anti-clockwise direction). The length of the spring determines the rate of oscillation of the balance wheel, which must undergo fine adjustment and regulation by the watchmaker to set the rate and accuracy of the watch. In high-end movements each balance spring is specifically matched to a particular balance wheel, at time of assembly, to ensure the most accurate performance is obtained. The balance spring is also known as the hairspring.

Balance Staff

The shaft or arbor upon which the balance wheel oscillates in its continuous backwards and forwards rotation.

Barrel

The component of a mechanical watch movement that contains the wound-up mainspring of the watch that stores its energy. The barrel consists of a cylindrical drum with a toothed rim that drives the gear train of the watch as it slowly unwinds. The mainspring is a coiled spring that can be wound up either manually by means of the crown (in a hand winding watch) or through the movement of an oscillating weight, called a rotor, in an automatic watch.

Base Plate (Main Plate)

The main structural plate that is used in mechanical watch movements to mount other components.

Beats per Hour (BPH)

The balance of a mechanical watch movement consists of a balance wheel that continually oscillates (rotates) backwards and forwards on its axis, each time releasing a small, incremental forward movement of the watch's escapement and gear train. The balance is responsible for the regulation of time. Each clockwise or counter clockwise swing of the balance wheel is called a "beat". The beats per hour (BPH) is thus a count of the number of to-and-fro swings of the balance wheel, measured over one hour. Also called a "vibration" (thus VPH), a beat is therefore defined as one half of a full-cycle oscillation (called the frequency) of the balance. Each full cycle thus consists of two beats, one being the forward swing and one the backward swing. Common BPH values are 21,600 (frequency of 3Hz) or 28,800 (frequency of 4Hz) beats per hour, however values of 18,000 (2.5Hz) and 36,000 (5Hz) are also sometimes used. (see also Frequency)

Bridge

A flat, structural piece of metal fixed at both ends to the base plate in a mechanical movement. A bridge is used to mount the rotating pivots of gearing wheels and other moving parts.

Cannon Pinion

In a mechanical watch movement, the cannon pinion controls the gear train that drives the hour, minute and seconds hands as part of the motion works mechanism.

Decorated Movement

Aesthetic modifications made to the movement of a watch to beautify it. Techniques used commonly include Côtes de Genève (Geneva stripes), perlage, bluing or polishing of screw heads, fine engravings, use of sunburst patterns on metalic parts, and bevelling and polishing of edges (anglage). Whilst decoration does not improve the function of the watch, it does indicate a level of attention to detail and pride of the watchmaker in their craftsmanship. Decoration is typically performed only on high-end and luxury mechanical watches. Some watches show off the decorated movement through the use of a transparent case-back.

Ebauche

A term used to describe a mechanical movement blank i.e. an incomplete watch movement manufactured with the purpose of being assembled into a completed watch by some other entity. It usually comprises of the raw, unassembled and unfinished movement, including the major structural components (e.g. plates, bridges) and sometimes parts of the gear train and other moving parts, but without the escapement, balance, hairspring and mainspring.

Escapement (including the Escapement Wheel)

A mechanism in a mechanical watch that controls the rotation of the wheels and thus the motion of the hands, in precise and evenly timed steps. It also delivers a small impulse to the balance wheel to keep it continually oscillating. Because of its distinctive anchor-shaped lever appearance it is often called a lever escapement, anchor escapement or Swiss lever escapement. The parts of a standard escapement include the escape wheel and pinion, the lever (anchor) with its pallet arms and pallets, the banking pins, the fork, and the impulse pin. The escapement pallets continuously engage (lock) and disengage (release) from the teeth of the escape wheel to control the rotation of the gear train. The pallet lever that holds the pallets includes one entry and one exit pallet. The escapement is the source of the "ticking" sound of a mechanical watch. The escapement is located between the gear train and the balance wheel.

Fast Beat Watch or Movement

A watch that has a balance wheel which beats or vibrates (oscillates) at a high rate such as 28,800 or more beats per hour. (see also Beats per Hour (BPH))

Fine Adjustment

A regulating lever or other mechanism used to precisely adjust the balance frequency in very fine amounts to make the watch as accurate as possible.

Gear Train (Wheel Train)

The system of gears (also called wheels) in a mechanical movement that transmits power, via a series of wheels and pinions, through the watch, starting from the main wheel (part of the mainspring and barrel), to the centre wheel, then to the third wheel, to the fourth wheel and finally to the escapement and balance. The hands of the watch are driven either directly or via additional wheels from the centre, third or fourth wheels.

Glucydur Balance

A type of high-quality balance wheel made of a special alloy comprising of beryllium, copper and iron. This alloy has excellent hardness, is non-magnetic, is resistant to corrosion, and has a low coefficient of thermal expansion, which makes the balance wheel very stable over a range of temperatures and assures high accuracy of the movement.

Hack or Hacking (Stop Seconds)

Also known as a 'stop seconds' function, hacking is a feature of some mechanical watch movements that stops the seconds hand when you pull the crown all the way out to the time setting position, thereby allowing the time to be set precisely "to the second" when synchronised with a time signal or known accurate clock. This is achieved in the mechanism by the use of a brake or lever that comes into contact with the rim of the balance wheel, thus causing it to stop and to be held in position. Pushing the crown in again releases the brake or lever, allowing the balance wheel to move freely once more and hence restarting the seconds hand.

Jewels

Jewels, usually a form of synthetic ruby, are used in the bearings of a mechanical watch movement to reduce friction and wear. They are used as bearings at pivot points of greatest friction in the movements. 17 jewels is generally the lowest number needed for most standard mechanical watch movements, however movements that comprise of various complications such a chronographs may use 21 or more jewels. Because of their hardness, jewels are also used on the escapement lever to engage the teeth of the escape wheel (pallet jewels) and on the impulse roller of the balance wheel (impulse jewel). Unlike real rubies, these synthetic rubies have no inherent monetary worth.

Keyless Works

The parts of a mechanical watch movement that does the winding and hand setting and includes the stem, clutch, clutch lever and intermediate wheel.

Mainspring

The mechanism in a mechanical watch that stores the power (energy). The mainspring is housed inside the barrel, a cylindrical drum with a toothed rim that drives the gear train of the watch. The mainspring consists of a flat, coiled spring that gradually uncoils, causing the barrel to rotate slowly on its arbor, keeping the watch's gear train in motion. The mainspring is wound either manually via the crown (manual winding) or by the movement of a rotor (automatic watch). Most watch mainsprings are made of nivaflex, an alloy that is elastic and relatively resistant to breakage.

Manufacture (Manufacture d’horlogerie)

In the watch industry, a manufacture, pronounced the French way, is any company that designs, produces and assembles all the parts of a watch in-house. The word manufacture is short for "manufacture d'horologie". Typically, any watch produced by a watchmaker that is a manufacture and contains an in-house movement, is generally considered more desirable and can thus often command a higher price.

Motion Works

The part of a mechanical watch movement that drives the watch hands, and includes the centre wheel, hour wheel, minute wheel and cannon pinion.

Pallet

The jewels, usually synthetic rubies, which are used in the escapement mechanism that continuously engage (lock) and disengage (release) from the teeth of the escape wheel to control the rotation of the gear train, allowing it to rotate in precise and evenly timed steps. The pallet lever that holds the pallets includes one entry and one exit pallet.

Pinion

A toothed wheel (gear) that combines with a larger wheel to form part of the gear train of a mechanical watch movement. The pinion of a wheel is used to in turn drive other wheels.

Power Reserve

A measure of the amount of time a watch will continue to run once fully wound, without needing to be rewound. The power reserve of most mechanical watches is generally about 35 to 42 hours. The power reserve for a watch can be obtained from its published specifications or instruction manual. On battery operated quartz watches, the term is sometimes used to refer to the expected battery life, typically 1 to 3 years.

Regulator

The mechanism used for the adjustment or regulation of a mechanical movement to increase its accuracy. This is usually done by a regulation mechanism that lengthens or shortens the active section of the balance spring (hairspring). The shorter the length the more rapidly it brings the balance back from each extreme of its oscillation (i.e. decrease in amplitude), which makes the movement run faster. The longer the length the slower it will run (i.e. increases its amplitude).

Rotor

The part of an automatic (or self-winding) mechanical watch movement that winds the movement's mainspring. It is a flat piece of metal, usually shaped like a semicircle, that swivels back and forward on a pivot with the motion of the wearer's arm that, via a series of gears, winds the watch's mainspring.

Shock-Resistant, Shock-Absorption or Anti-Shock

A system of resilient bearings and spring devices used in the balance-wheel bearings to protect the delicate, fragile pivots on the balance staff against breakage in the event of a sudden impact. When the watch is subjected to a strong blow, these springs and bearings provide some “give” laterally and/or vertically as required and allow the balance-wheel to return to its original position. Names of systems used for shock protection include Incabloc, Kif, Etachoc, Parachoc, Paraflex, Unisafe and Nivachoc.

Wheel

Another name for a 'toothed' gear used in a watch movement.

Functions

Altimeter

A watch function that displays the current altitude (or height above sea level) by responding to changes in barometric pressure. An altimeter is a function commonly found in pilot watches but is also an important function for mountain climbers and rock climbers.

AM/PM Indicator

(see Day/Night or AM/PM Indicator)

Annual Calendar

A calendar mechanism on a watch that adjusts automatically to account for short and long months (i.e. 30 or 31 day months). The calendar needs re-setting once every year at the end of February in non-leap years only. While not always the case, a watch with an annual calendar displays the date, the day of the week, and the month.

Calendar

A function on a watch that displays calendar information, such as the date, the day of the week, the month, and sometimes, the year in a leap year cycle. There are several variations, including those that show the date only (a simple calendar), those that show the date and day (a day/date calendar), those that show the date, day and the month (a triple calendar), and those that show the date, day, month and the year in a leap year cycle (a perpetual calendar). There are also variations of these such as an annual calendar feature that adjusts automatically to account for short and long months (i.e. 30 or 31 day months).

Centre Seconds

A seconds hand that is attached at the centre of the main dial along with the hour and minute hands, as opposed to being located in a sub-dial.

Chronograph

A watch function that measures elapsed time similar to a stopwatch. Most chronograph watches have two or three sub-dials for measuring elapsed minutes and hours (called counters, register, accumulators or totalisers) and also a small seconds hand sub-dial. The chronograph elapsed-seconds counter is usually located at the centre of the main dial along with the normal hour and minute hands. A standard chronograph has two pushers on the side of the case, the top one is used to start and stop the chronograph function and the bottom one is used to reset all counter hands back to zero.

Chronometer

Refers to a high precision watch that has met certain high standards of accuracy. Chronometer watches are rigorously tested in various temperatures and positions, thus meeting the accuracy standards set by C.O.S.C. (Controle Officiel Suisse des Chronometeres) in Switzerland. The standard procedure involves measuring the performance of the movement at three different temperatures and in five different positions for fifteen consecutive days. Mechanical movements that are accurate to -4 to +6 seconds per day are awarded a chronometer certificate.

Counter

A sub-dial used in a chronograph function to record elapsed time. Often a chronograph watch will have two separate sub-dials, one sub-dial to record elapsed time for minutes and one sub-dial to record elapsed time for hours. Elapsed-seconds is usually recorded on the centre seconds hand. (also sometimes known as a register, accumulator or a totaliser)

Day/Date Calendar

A calendar mechanism on a watch that displays both the date and the day of the week.

Day/Night or AM/PM Indicator

A watch function that displays whether the present time is AM or PM. This function can be found mostly in watches with a GMT/dual time or a world time display to show whether it is day or night in the other time zone.

Divers Watch

A watch intended for use while scuba or deep-sea diving. Divers watches commonly feature a graduated, rotating bezel that is used by the diver to monitor their dive time, a screw down winding crown for enhanced water resistance, a clear, highly visible time display (including lume), a water resistance rating to at least 200 metres (20 ATM/20 BAR), and, for professional and deep-sea divers, a helium release valve.

Dual Timer/Dual Time Zone Watch

A watch that measures current local time as well as the time in at least one other global time zone. This is commonly displayed by an additional hour hand or a 24-hour hand that tracks time in a 24 hour mode. A dual time zone watch can also be called a GMT watch, which assumes the second time zone will be set to GMT.

Equation Of Time

A function which indicates the difference between conventional time, called 'mean time', and the time determined by the position of the sun, called the 'real' or 'true' time. As the earth orbits around the sun in an elliptical (oval) shape and the axis is tilted, there are only four days a year when the day is exactly 24-hours long i.e. April 15th, June 14th, September 1st and December 24th. For all other days of the year the days are either shorter or longer, depending on the position of the earth. This difference ranges between -16 and +14 minutes, depending on the day of the year. An equation-of-time display shows this difference.

Flyback Chronograph (Retour-en-vol)

A special type of chronograph in which the elapsed seconds hand can be stopped, returned to zero and restarted instantly with a single push of a pusher button. Restarting a standard chronograph requires three button pushes and two buttons to achieve the same action, requiring that you stop the timing with a push of the first button, return the hand to zero with a push of the second button, and restart the hand with a push of first button again. A flyback function is useful for timing a rapid sequence of events such as the laps in a race by allowing instant reset and restarting of the chronograph.

Grande Complications

A "Grande Complication" is a watch that combines a minute repeater, split-seconds chronograph, and perpetual calendar functions in one watch. Watches with grande complications are extremely complex and include intricate mechanisms with many hundreds of parts. They can be produced by only the most highly decorated watchmakers and high-end watchmaking enterprises. They occupy the very high-end and luxury-end of the market and are thus very expensive.

Helium Escape Valve

A function on professional divers' watches specifically designed for deep-sea diving conditions. The valves, located on the side of the watch case, are only needed for divers that spend several consecutive days in pressurised deep-sea chambers. Under these conditions, tiny molecules of gas in the breathing mixture (helium and other gasses) penetrate the watch. These gasses expand when the diver ascends in a diving bell, which can damage the watch. The valve allows the gasses to escape without harming the watch case. A helium release valve can operate either automatically, which does not need to be unscrewed manually, or manual, which is manually operated via a special screw-down crown.

Moon Phase

A function on a watch that includes a display that keeps track of the phases of the moon by means of a specially shaped aperture on the dial. This consists of a disk printed with two full moons that rotates beneath an aperture on the dial. As it turns, portions of the moons become visible within the aperture that corresponds to the present moon phase. A regular rotation of the moon is once around the earth every 29 days, 12 hours and 44 minutes. The indicators of moon phase watches commonly show the moon through 29 1/2 days, which implies the need for a manual adjustment every two and a half years to recover the one day lost with respect to the real state of the moon phase. Some moon phase watches however incorporate a correction for the extra 44 minutes per month.

Perpetual Calendar

A calendar function that displays the date, day of the week, the month and the leap year cycle, and adjusts automatically to account for the different lengths of the months (30 or 31 days) and February days in non-leap years and leap years (28 or 29 February days). Perpetual calendar watches will remain accurate until February 28, 2100 when they will need to be reset. This is due to an anomaly in the Gregorian calendar that says 2100 will not be a leap year despite being divisible by four. Watches with a perpetual calendar function are generally very expensive.

Pilot's Watch

A watch designed with features and functions specifically for use in aviation. Common features include good legibility with limited use of logos, a matte or satin finish on the case and black dial to limit reflection, individual minute markers, large fluted crown and a luminous display. Other more traditional features include a calfskin strap with contrasting white stitching, diamond shaped hands that differ in width for easy identification and a triangle flanked by a pair of dots as an additional hour index at 12 o'clock.

Power Reserve Indicator (Reserve de Marché)

A display on a watch that shows how much power remains in a watch's mainspring before it must be rewound. It is usually indicated in terms of the number of hours. The power reserve of most mechanical watches is generally about 35 to 42 hours. Another name for a power reserve indicator is Reserve de Marché.

Pulsimeter or Pulsometer

A scale on the dial or bezel of a chronograph watch used for measuring a pulse rate. A pulsimeter scale is always marked with a reference number. If for example it is marked with "graduè pour 15 pulsations", then the wearer would start the chronograph and count fifteen pulse beats. At the last (15th) beat, the chronograph would be stopped and the elapsed time seconds hand will show on the pulsimeter scale what the pulse rate is in beats per minute. (see also Asthmometer for measuring respiration rate)

Rattrapante (Split Seconds or Double Chronograph)

A special type of chronograph that uses two centre seconds hands. It uses a special push-piece and an additional mechanism to make it possible for the rattrapante to time intermediate events such as a single lap of a multi-lap race while allowing the main chronograph to continue to run, timing the entire race. When the chronograph is first started both hands start together, one sitting directly over the top of the other. The extra seconds hand runs concurrently with the main chronograph hand but can be repeatedly stopped, started or reset to zero, independently, to record an intermediate time, while the main chronograph seconds hand continues to run. The extra seconds hand can also be restarted, causing it to "fly-back" to catch up with the constantly moving elapsed-time hand. In order to stop and reset both hands to zero the rattrapante has a return pusher. This function is also sometimes called a split-seconds chronograph or a double chronograph.

Repeater

A repeater is a watch function that can acoustically chime the time on demand by the wearer by means of push piece, called a slide, on the watch case. The wearer pushes the slide, which winds a spring to trigger the repeater mechanism. The repeater mechanism is a system of hammers and gongs. A chime involving more than two gongs of varying tones is called a carillon. There are several variations of the repeater. A quarter repeater sounds the hours and quarter hours only. A minute repeater however can chime the time to the latest minute by producing chiming sounds corresponding to, in order, the hour, quarter-hour and minute. Other types of repeaters can chime the time to the last 1/8-hour (7 1/2-minute), or 5 minutes. Watches with a repeater function are generally very expensive.

Retrograde

A function display or indicator hand on the dial of a watch, usually in a sub-dial, that moves in a semi-circular or arc type motion, instead of around in a full circular path as most indicators do, to display its range of values. When the hand reaches the end, it instantly snaps back to its starting position. For example a watch with a retrograde date, will have a hand that moves through an arc from 1 to 31 during the course of the month, and at midnight on the 31st day, will flip back in the opposite direction to point to the number 1, for the first day of the next month.

Rotating Bezel

The bezel of a watch is the metallic ring that surrounds the watch face or dial. A rotating bezel is a special type of bezel that can be turned. This is used for a certain function, such as to show elapsed dive-time on a divers' watch or to indicate a particular time zone of a city on a world time watch. Rotating bezels can be designed to rotate in both directions or in one direction only.

Screw-down Crown

Also called a screw-locking crown, a screw-down crown is a special type of watch crown that can be screwed into the watch case to enhance its water resistance. This works by using a threaded crown that in turn screws into a matching thread on a tube which protrudes from the case of the watch. The crown has a gasket that is compressed and seals the opening when the crown is tightened down. A screw-down crown is an important feature for any watch you intend to swim with.

Simple Calendar

A calendar mechanism on a watch that displays the date only. Simple calendar watches usually don't take account of the varying lengths of months and must be reset by hand at the end of each 28 or 30 day month.

Small Seconds

A seconds hand that is displayed in a sub-dial, rather than in the centre of the main dial, as is more commonly found. Small seconds is a common feature of chronograph watches however, with the centre seconds hand being used as the elapsed seconds counter.

Sonnerie (en passant)

A variety of a repeater function that chimes the hours and minutes en passant (automatically), similar to a grandfather clock or clock tower, rather than at the demand of the user like a standard minute repeater. The chime sounds are obtained by a mechanism called the striking work, made up of hammers striking gongs. A sonnerie that strikes on the hour is called a petite sonnierie (or lesser strike). A sonnerie that strikes the hour and the quarter hours is called a Grande Sonnerie (or grand strike). These watches are also equipped with a device that silences the chimes when desired. Watches with a sonnerie function are generally very expensive.

Sun/Moon Indicator

A function on a watch that indicates the position of the sun and moon over a 24 hour period.

Tachymeter (or Tachometer)

An additional feature on some chronograph watches whereby a specially calibrated numerical scale is printed around the dial or on the bezel of the watch, that can be used in conjunction with the chronograph function to measure one's approximate speed, as measured over a known distance. To use the function the wearer starts the chronograph when passing the starting point and stops it when passing the finish point. The speed, in units per hour, can then be read off the tachymeter scale. This works however only for periods of observation of less than 60 seconds.

Telemeter

An additional feature on some chronograph watches whereby a specially calibrated numerical scale is printed around the dial or on the bezel of the watch. It can be used in conjunction with the chronograph function to measure the distance of a phenomenon that is both visible and audible, such as a lightning strike and its associated thunder clap. To use the function the wearer starts the chronograph at the instant the lightning is seen, and stopped when the thunder clap is heard. The distance in kilometres or miles separating the position of the lightning to that of the wearer can then be read off the telemeter scale.

Tourbillon

The tourbillion was first developed around 1795 by the French-Swiss watchmaker Abraham-Louis Breguet. It is a mechanism designed to compensate for the differences in rate observed when a watch is held in different positions. To counter these effects of gravity on the watch's accuracy, the tourbillon involves mounting the escapement and balance wheel in a rotating cage. The cage rotates around its own axis, usually at the rate of once per minute. This continual rotation of the escapement and balance wheel nullifies the effects of these positional errors when the watch is in a vertical position, going through all positions to average out the errors, and thus supposedly improving the accuracy of the timepiece. The tourbillon has no effect on the accuracy when the watch is in a horizontal position. The tourbillon is an extremely delicate and complex mechanism and is beautiful and quite mesmerising to observe. They are considered by many a form of mechanical art and objects of curiosity. Tourbillons are thus highly prized in today's wristwatches. To design and build a tourbillion watch requires intricate micro-engineering capability and extraordinary watchmaking know how and expertise. Something typically reserved for only the most highly decorated watchmakers and high-end watchmaking enterprises. Today, variations in tourbillon designs include the double and triple-axis tourbillons, double and quadruple tourbillons and the flying tourbillon. Tourbillon is French for "whirlwind."

Triple Calendar

A calendar mechanism on a watch that displays the date, day of the week, and the month.

World timer

A function on a watch which tells the time in up to 24 time zones around the world. A world time watch shows the time simultaneously in the world's time zones using two rings. The time zones are represented by the names of prominent cities from each time zone evenly positioned around one ring, the other ring is marked with hour numerals, usually in 24-hour time (1 to 24). The two rings rotate in reference to each other. The wearer reads the hour in a particular time zone by looking at the hour numeral next to the city in that time zone. Some world timers track the time zones automatically (one of the rings rotates caused by the watch movement itself) whereas others require a manual rotation of the world timer's bezel each occasion the time is required in a different time zone. With the latter, the manual ring can be re-positioned by referencing the local time. The minutes are read from the main dial as normal.

Basic watch anatomy

Analog or Analogue Watch

A watch that displays the time by means of an hour, minute and (sometimes) a second hand on the dial of the watch (as opposed to a digital watch that shows the time using a digital display).

Analog/Digital (Duo) Display (or Anadigi)

A watch that exhibits features of both analogue and digital type watch displays.

Arabic Numerals

Dial index numbers written in the form 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12. (as opposed to the use of roman numerals or baton index markers)

Automatic (Self-winding) Movement

A mechanically powered watch that is wound by the motion of the wearer's arm rather than having to be manually wound using the crown. The natural motion of the wearer causes a rotor, a semi-circler shaped piece of metal, to swivel around its pivot which winds the watch's mainspring. Many automatic watches however can also be manually wound via the crown if required. Automatic watches are also called self-winding watches.

Automatic Watch

A mechanical watch that uses an automatic movement. Automatic watches are also sometimes called self-winding or perpetual watches. (see also Automatic (Self-winding) Movement)

Band

A generic term used to refer to the band that holds the watch on the wrist. More specific terms are a bracelet (made of metal) or a strap (usually leather, nylon, canvas or rubber).

Baton Index Markers

Non-numerical 'stick' type indices or markers located on the dial of a watch that mark the hours and minutes. (as opposed to the use of arabic or roman numerals)

Bezel

The ring, usually made of metal alloy or ceramic substance, that surrounds the watch face or dial. Often it serves as specific purpose such as the calibrated markings that are used to measure the elapsed dive time as found on a divers watch or to indicate a second time zone on a world time watch. The bezel may also contain embellishments such as diamonds or other decorations for aesthetic purposes.

Bracelet

The name commonly used to describe a watch band made of metal such as stainless steel, titanium, platinum or gold. The bracelet is comprised of interconnected links, and is secured to the watch case using spring bar type pins and to each other using either split pins or screw-in type pins. You can change the length of the bracelet by removing or adding links. The "number of links" specification of a bracelet refers to the number of links across its width. Commonly, bracelets are 3, 5 or 7 link bracelets.

Buckle

Used to join the watch strap together around the wearer's wrist. The buckle is often made of the same material as the case of the watch.

Case

The exterior metal (usually) housing or covering of a watch. The case is commonly made up of three parts, the middle, the bezel, and the case-back. Stainless steel is the most common material used, however ceramics, titanium, gold, silver and platinum can also be used.

Case-back

The metal cover on the back of a watch, which can be removed to expose the watch's movement. A case-back can either snap into place or can be a screw down type.

Chapter Ring

A raised ring sometimes used around the outer edges of a watch dial, commonly used to display second or sub-second increments.

Clasp

The latch or catch used to fasten the two ends of the watch bracelet around the wrist and to open and close the watch bracelet. There are many different styles and deployment mechanisms used for the clasp. They can use a single or double foldover mechanism (with or without a safety latch), a latch that snaps closed around a bar, they can have a 'box and tongue' type locking mechanism. There are also several other varieties in existance. They can also be either a clip-down type or have deployment buttons on each side that are used to release it. The clasp is usually made of the same substance as the metal bracelet itself.

Complication

Used to describe any additional function on a watch, other than the standard time keeping function and a simple date calendar. Complications can include functions such as triple, annual or perpetual calendars, chronographs, power reserve indicators, repeaters, moon-phase displays, equation of time, day/night indicators, 24-hour hands, GMT or world time displays, tourbillons and retrograde hands. A "Grande Complication" is a watch that combines a minute repeater, split-seconds chronograph, and a perpetual calendar in one watch.

Crown

A knob on the side of the case that is turned to wind the watch's mainspring (on mechanical watches) and is used to set the hands and other functions of the watch. On diving and sports watches the crown may be a "screw-down" type, whereby it screws onto a threaded tube which protrudes from the case of the watch with the intention of increasing its degree of waterproofing.

Crystal

The transparent protective cover that sits over the dial or face of a watch. Three types of crystals are commonly found in watches, an acrylic crystal (sometimes called hesalite or plexiglass), which is plastic, is the least expensive option, a mineral crystal, which is ordinary glass that has been heat treated for additional hardness, and sapphire crystal, a synthetic material with the same chemical composition as natural sapphire, which is highly resistant to scratching. Sapphire crystal is the most expensive and durable alternative and is approximately three times harder than mineral crystals and 20 time harder than acrylic crystals.

Dial

Refers to the face of the watch that is visible through the crystal on the front of the watch. The dial includes the dial face itself, the watch hands and associated indices or markers for showing the hours, minutes and seconds, along with any other indicators for other functions of the watch.

Digital Watch

A watch that uses a digital display to tell the wearer the time.

Function

A term used to describe the various tasks a watch can perform. These are also known as complications. A function can include calendars, chronographs, power reserve indicators, repeaters, moon-phase displays, equation of time, day/night indicators, 24-hour, GMT or world time displays, tourbillons and retrograde hands. A "Grande Complication" is a watch that combines a minute repeater, split-seconds chronograph, and a perpetual calendar on the one watch.

Horology

The art or science of making timepieces and of measuring time. The term is most often used to refer to the study, design and construction of mechanical timepieces.

Hour Hand

The watch hand that shows the time of the current hour. The hour hand rotates around the dial once every 12 hours. The hour hand is generally the shortest of the central watch hands.

Index or Indices

The markings (e.g. stick or baton markers) around the outer edges of the dial which shows the hours and minutes.

Lug

The extension pieces on the top and bottom of the watch case that are used to attach the watch strap or bracelet. Normally, straps and bracelets are attached to the lugs with removable spring bars. Lugs are also commonly known as the horns.

Luminescence or Lume

A substance that is applied to the watch hands and other parts of the dial such as the indices, markers or numerals to allow the time to be read in the dark. By absorbing energy from electromagnetic light rays when there is light is present allows the lume to effectively "glow in the dark" by reflecting back light for some period of time. This is achieved using 'photo-luminescent' or 'afterglow' pigments. Lume is most commonly found on sports and divers' watches.

Manual Winding Watch

A type of mechanical watch whose mainspring must be wound every day or two by turning the crown, to keep it running. Once fully wound, the watch will stay running for the specified amount of time, generally about 35-45 hours, as denoted from the 'Power Reserve' specification for the watch. This is the oldest method of powering a watch, and while much less common today, manual-wind watches are quite popular with those that appreciate traditional watchmaking methods. Manual-wind watches are still available from a number of the finer watch manufacturers. Automatic watches in contrast, are mechanical watches that can be wound automatically by the motion of the wearer's arm. Manual winding watches are also called a hand-winding watch.

Mechanical Movement

A watch with a mechanical movement is one of the two predominant watch types, the other being a watch with a quartz movement. A mechanical watch movement is made completely of mechanical parts. Unlike quartz movements, they contain no battery or electronic components. The watch's mechanism is composed of hundreds of parts including springs, gears or wheels, and screws etc., which must be assembled by hand. There are two types of mechanical movements, manual-winding and automatic. A manual-winding movement must be wound every day or two by turning the crown, to keep it running. Automatic movements in contrast, can be wound automatically by the motion of the wearer's arm. Mechanical movements are the traditional, time-honoured watch movements that have been produced for hundreds of years. Many watch lovers feel mechanical movements are more interesting and appealing because of the skill and craftsmanship necessary to design and build them. While not always the case, quartz watches generally comprise the low to mid end of the watch market, whereas mechanical watches largely dominate the mid to high and luxury end of the watch market. Mechanical watches can be identified by the (almost) continuous "sweeping" motion of the watch's second hand, unlike those on a quartz watch that jump forward in one second intervals.

Mechanical Watch

A watch that contains a mechanical movement. (see Mechanical Movement)

Minute Hand

The watch hand that shows the time of the current minute. The minute hand rotates around the dial once every hour.

Movement

The inner mechanism of a watch that keeps time and powers all aspects of the watch, including moving the watch's hands and any calendar, chronograph or other functions. The case, crown, dial, hands and crystal are not considered part of the movement. The two predominant watch movement types are mechanical and quartz. A mechanical watch movement is made completely of mechanical parts and requires no battery, whereas quartz movements require a battery and have electronic components. While quartz watches currently enjoy a much larger market share, mechanical watches are now seeing a significant uptick in popularity. Specific models of movements are referred to as calibres.

Open Heart

A watch with an open heart is a mechanical watch with a viewing apperture or window on the face of the dial that allows the balance wheel and (optionally) excapement mechansm to be seen.

Pusher, Push-Piece or Push-Button

An additional actuator button mounted on a watch case that is pressed to work a specific function. Push-pieces are generally found for example on chronographs and repeater watches.

Quartz Movement

A watch with a quartz movement is one of the two predominant watch types, the other being a watch with a mechanical movement. Unlike mechanical movements that have all mechanical parts, quartz watches are battery powered and contain electronic components. A quartz watch movement uses a quartz crystal oscillator (hence its name) as its core timekeeping source and regulation mechanism. Nearly all modern quartz movements have a frequency of 32,768 oscillations per second. Because quartz movements have electronic circuitry they require a battery to power them, which distinguishes them from mechanical watches which do not. The battery in a quartz movement will usually last about 1 to 3 years. Watches that are powered by quartz movements are generally more accurate than a watch with a mechanical movement. Most are accurate to within 10 seconds per month. They are also generally more amenable to mass production which makes them less expensive than most mechanical movements which require a higher degree skill and craftsmanship to build. While not always the case, quartz watches generally comprise the low to mid end of the watch market, whereas mechanical watches largely dominate the mid to high and luxury end of the watch market. Quartz watches can be identified by the seconds hand, that jumps forward in one second intervals, rather than the more sweeping motion of the seconds hand on a mechanical watch.

Quartz Watch

A watch that is powered by a quartz movement. Quartz watches require a battery to power them. They are available in both digital and analogue types. Digital watches have a digital readout whereas an analogue watch shows the time by traditional hour, minute and seconds hands on the watches dial.

Roman Numerals

Dial index numbers written in the form I, II, III, IIII, V, VI, VII, VIII, IX, X, XI and XII. (as opposed to the use of arabic numerals or baton index markers)

Seconds Hand

The watch hand that displays the time of the current second. The seconds hand rotates around the dial once every 60 seconds (1 minute).

Skeleton Watch

A watch with a transparent face or dial to allow parts of the movement to be seen. The movements in skeleton watches are also often designed to show as much of the more interesting aspects of the mechanism as possible. Skeleton watches are only used on watches with mechanical movements as quartz watches little or no aspects of visual interest.

Strap

A term commonly used to describe a watch band made of any non-metallic substance such as leather, nylon, canvas or rubber.

Sub-dial (Subsidiary Dial)

A small auxiliary dial set within the main watch dial. Sub-dials can be used to display certain functions such as a seconds hand, counters of a chronograph, day or date, or a power reserve indicator etc.

Transparent Case-back

A special type of case-back that is transparent to allow the watch's movement to be observed. These are only used on mechanical movements as quartz watches have little or no aspects of visual interest.

Water Resistant

"A watch that is ""water resistant"" means it has 'some degree' of protection from water damage.

To find out what the degree of water protection is, you need to refer to the specifications published for the watch by the manufacture. The degree of water resistance may also be printed on the dial or elsewhere on the watch itself.

The specifications generally describe the amount of water resistance in either 'meters' of water pressure (for example '100 meters'), in ATM, or in BAR. These terms are generally synonymous however, where 1 ATM = 1 BAR = 10 metres of water pressure. For example a watch that is specified as having water resistance to 200 meters, this equals 20 ATM or 20 BAR.

The following is a guide to an appropriate level of usage:

- tested to 30 meters - can withstand light splashes of water. Not suitable for showering, bathing, swimming, snorkelling, water related work, diving or fishing.

- tested to 50 meters - suitable for showering or swimming in very shallow water only.

- tested to 100 metes - suitable for recreational swimming or snorkelling.

- tested to 200 meters - suitable for amateur scuba diving.

- tested to 300 meters or more - professional or deep-sea diving.

Note: The water resistance refers to the amount of water pressure the case can withstand, not the depth to which the watch can actually be worn. Water pressure specifications apply to a watch immersed in completely motionless water only, under laboratory testing conditions. A watch worn on a wearer's wrist while showering or swimming is subject to far greater pressure, due to the motion of the water and/or the wearer's arm through the water.

Quartz watches

Battery EOL

A battery "End of Life" indication found on some quartz watches that warns the wearer of approaching battery failure. It usually entails the second hand jumping forward in two or four second intervals rather than the usual one second interval.

Battery-less Quartz

A type of quartz watch that uses a charged capacitor or rechargeable battery to continually power the watch rather than a standard battery. The advantage being that the watch does not need the periodic battery replacement as with a standard quartz watch. Instead, the capacitor or rechargeable battery is continuously recharged by an internal rotor that pivots on an axis caused by the movement of the wearer's arm. Also known under various marketing names, including Kinetic (Seiko) or Omega-matic (Omega). Alternatively, the capacitor or rechargeable battery can be recharged using natural or artificial light, such as in Citizen's Eco-Drive technology.

Caliber or Calibre

An alphanumeric name or number that identifies the manufacturer, model, series and type of watch movement.

Digital Display

The display of the time using numbers on an electronic LCD display. An LCD (Liquid Crystal Display) on a quartz watch is the most common form of digital display. (as opposed to an analogue display that uses hands on the dial to tell the time)

Liquid Crystal Display (LCD)

A digital watch display that shows the time as a series of electronic numbers. Each individual numeral is made up of seven individual segments that form the number 8 when all are activated. Each number (1 to 8) is displayed by activating only the relevant segments by means of an electronic current. The technology works by means of a liquid held in a thin layer between two transparent plates. All LCD digital watches have quartz movements.

Quartz Crystal Oscillator

A quartz crystal oscillator is an electronic oscillator circuit that uses the resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise and consistent frequency. This frequency is used to provide the stable clock signal source in quartz watches.

Solid State

A watch movement with no moving parts. All quartz digital watches are 100% solid state. Analogue quartz and mechanical watches however have moving parts such as wheels and gears and are thus not considered solid state.

Stepping Motor

A battery powered electric motor used in an analogue watch with a quartz movement that moves the gear train and in turn the watch's hands. It is called a stepper motor because it divides a full rotation of its shaft into a number of small, equal steps, hence the per-second steps characteristic of the second hand of an analogue quartz watch.

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