Lido Watch Club – Illustrated Glossary of Horological Terminology

Click on any of the letters below to learn more… Note that we’ll continue to update the glossary.



A watch provided with a movement capable of releasing an acoustic sound at a pre-set time.


Combination of two or more pure molten metals. Generally, an alloy is given the name of the dominant metal.


A device that determines altitude by responding to changes in barometric pressure.

Analog or Analogue

A watch that shows the time using hour and minute hands; as compared to a watch with a digital or numeric display.

Annual Calendar

An Annual Calendar complication displays the day, date and month with the need for manual adjustment only in February to account for leap years.


The movement of a mechanical watch can be thrown off balance if it comes in contact with a strong magnetic field; Magnetism is common


in loudspeakers, televisions, refrigerators, cars, etc. and these days most watches claim to be anti-magnetic. This is achieved by using alloys for certain parts, among them the balance wheel and escape wheel. Electronic watches are not susceptible to magnetism.



A small opening in the dial. In an aperture watch, various indications such as the month, moon phase, day, date, hour, minute, etc. are visible through these openings.

Arabic Numerals

Numbers – e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12; as compared to Roman Numerals I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII.


The axle of a wheel or gear that turns in a bearing or jewel; e.g. barrel arbor, winding arbor, pallet arbor, etc.

Atomic Watches

The watch can receive signals from six atomic clock radio broadcasts worldwide providing unerring timekeeping. The U.S. government


operates an “Atomic Clock” in Boulder, CO. This Atomic Clock will not gain or lose a second in 60 million years.


Automatic Movement

This term refers to a watch with a mechanical movement (as opposed to a quartz or electrical movement). The watch is wound by the motion


of the wearer’s arm rather than through turning the winding stem. A rotor that turns in response to motion winds the watch’s mainspring. If an automatic watch is not worn for a day or two, it will wind down and need to be wound by hand to get it started again.




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


This is essentially and oscillator which regulates the speed of the movement of a


mechanical watch.


Balance spring

An extremely delicate coil-like spring, moving the balance back and forth.

Balance wheel

Similar to a clock pendulum, the balance wheel oscillates to split time into equal segments.


A cylindrical shape containing the mainspring of a timepiece.


A device that transform the energy created by a chemical reaction into electrical energy.


Typically, a battery lasts for two to five years. Its lifespan will depend on the type of watch, its size and the amount of energy required for the different functions. A chronograph will consume more energy than a watch that shows only hours, minutes and seconds.

Special lithium-iodine batteries have a theoretical lifespan of 10 years.


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.



A feature found on some watches, measures the atmospheric pressure.


The ring surrounding the watch face, often decorated or adorned with hour markers or a tachymetric scale.

Bi-directional 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


Built-in Illumination

Lighting on a watch dial that allows the wearer to read the time in the dark.


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


Variously-shaped ring for suspending a pocket watch and fastening a chain.



Built-in Illumination

Lighting on a watch dial that allows the wearer to read the time in the dark.



Decorative stone which has been carved into a round shape.




A feature that shows the date, and often the day of the week. There are several types of calendar


watches. Most calendar watches show the information digitally through an aperture on the watch face. Some chronograph watches shoe the information on sub-dials on the watch face.



The horological term for a watch movement, these can be mechanical or quartz.


The case of a watch must not only protect the mechanism and hold all the parts together but it must also look good sometimes to the extent of making a timepiece into a piece of jewellery.


A watch case is generally in 3 parts:
the bezel, which holds the crystal,
the band or centrepart, which contains the movement,
and the back, either snapped or screwed on, in to which, sometimes, is fitted a crystal so that an intricate mechanical movement watch



The reverse side of a timepiece. This can be covered, perhaps with engraving, or sapphire to be able to view the inner workings of the timepiece.

Case Materials

Materials range from inexpensive cast metal through molded plastic to solid chunks of steel or gold from which the case is machined. In Great Britain, gold cases are usually 18k,


but less expensive watches are 9k. In most other countries, 14k is preferred. Caratage indicates the gold content of metal, stated as the number of parts of gold in every 24 parts, i.e. 18k gold is 18 parts of gold alloyed with six parts of metal. Platinum is becoming increasingly popular, as is titanium for its lightness. Ceramic cases and bracelets a scratch resistant space age material formed under great pressure and heat from powder are used by some manufacturers. It does not bear any resemblance to the ceramics used in pottery. Some watches in the middle price ranges are gold plated over brass -9k or 18k plating usually. Vermeil is the term used to describe silver which has been gold plated.


Centre Seconds

Seconds indicated by a hand at the centre of the dial, along with the hour and minute hands.


From the Greek keramos meaning fired pottery. In watchmaking, ceramic is a high-
tech material, generally made from aluminium


and zirconium oxides (polycrystals) for the manufacturing of cases and decorative elements.


Chapter Ring

The ring on the watch dial bearing figures and minute marks. The hour figures are sometimes called chapters


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 on the chronograph. Some operate with a center seconds hand which keeps time on the watch’s main dial. Others use sub-dials to time elapsed hours, minutes and seconds. Still others show elapsed time on a digital display on the watch face. Some chronographs can be used as a lap timer (see “flyback hand” and “split seconds hand”). The accuracy of the stopwatch function will commonly vary from 1/5th second to 1/100th second depending on the chronograph. Some chronographs will measure elapsed time up to 24 hours. Watches that include the chronograph function are themselves called “chronographs.” When a chronograph is used in conjunction with specialized scales on the watch face it can perform many different functions, such as determining speed or distance (see “tachymeter” and “telemeter”) Do not confuse the term “chronograph” with “chronometer.” The latter refers to a timepiece, which may or may not have a chronograph function, that has met certain high standards of accuracy set by an official watch institute in Switzerland.



Technically speaking, all watches are chronometers. But for a Swiss made watch to be called a chronometer, it must meet certain


very high standards set by the Swiss Official Chronometer Control (C.O.S.C.). If you have a Swiss watch labeled as a chronometer, you can be certain that it has a mechanical movement of the very highest quality.



The attachment used to connect the two ends of the watch bracelet or strap around the wrist.
There are a number of clasp types commonly


used by the watch industry. The most common include:
Deployment Buckle: (also known as a fold-over buckle): Three-folding closure that secures two ends of a bracelet. When closed, the buckle covers the folding mechanism.

Push-Button Foldover Clasp With Safety: is a deployment clasp with a push-button mechanism that opens the bracelet, along with a fold over closure on top that provides a second layer of security.

Hidden Clasp: (also called butterfly clasp): Folds the sections under the watch band to make the bracelet appear as an uninterrupted chain.

Tang or Buckle Clasp: A buckle with a hook, the tang that fits into a hole on the watch strap

Jewelry Clasp: A hinged hook that folds over a bar to secure the watch band.


Closed Dial

A timepiece dial where it is not possible to see through into the inner workings of the timepiece.

Co-Axial Escapement

Is a type of modern watch escapement mechanism invented by English watchmaker George Daniels. Considered by many to be one


of the most significant horological advancements since the invention of the lever escapement, the co-axial escapement functions with virtually no lubrication thereby eliminating one of the shortcomings of the traditional lever escapement.



A compass that lets the wearer determine the geographical poles by means of a rotating bezel. The wearer places the watch so that


the hour hand faces the sun. He then takes half the distance between the position and 12 o’clock, and turns the bezel until its “south” marker is at that halfway point. Some quartz watches have solar compasses that show directions on an LCD display.


Complete Calendar

A Complete Calendar complication displays the day, date and month with the need for manual adjustment at the end of each month not 31 days long.


A complication is any further function on a timepiece beyond the keeping of regular time. For example, each of the following would be classed as a complication: date display, power


reserve indicator, moon phase. Complications vary in their degree of difficulty.



The skeleton of a marine animal. Coral polyps secrete a strong calcium structure that was often used for watch dials. It s colour ranges from pale pink (called angelskin coral) to


orange to red to white to black. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7.


COSC Certification

A Swiss standard of quality certification. An acronym for Controle Officiel Suisse des Chronometeres.


The cosmograph differs to the chronograph in that the tachymeter is on the bezel rather than on the outer rim of the dial. This was invented


by Rolex to create a more modern look to the watch.


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 as yacht races, where the sailor must maneuver the boat into position before the start of a race.



Also called a stem or pin, a crown is the button on the outside of the watch case that is used to set the time and date. In a mechanical watch


the crown also winds the mainspring. In this case it is also called a “winding stem”. A screw in (or screw down) crown is used to make a watch more water resistant. The crown actually screws into the case, dramatically increasing the water-tightness of the watch.



The transparent cover on a watch face made of mineral glass crystal, synthetic sapphire or plastic. Better watches often have a sapphire


crystal which is highly resistant to scratching or shattering.



Dauphine Hands

A wide, tapered hand with a facet at the center running the length of the hand.

Day/Night Indicator

A colored or shaded band on a world time that shows which time zones are in daylight and which in darkness.

Depth Alarm

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

Depth Sensor

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.



The face of a timepiece. Some dials have within them smaller dials for displaying the date, etc, called “subsidiary” dials, or “subdials.”

Digital Watch

A watch that shows the time through digits rather than through a dial and hands (analog) display.


Diamond is the hardest and most luminous precious stone. The price of a diamond is calculated according to the 4C criteria: Cut –


Carat – Clarity – Color. The weight of a diamond is expressed in carat: 1 carat is equal to 0.20 gram. Pure colorless carbon, in jewelry the diamond is cut into facets to increase its sparkle. In watchmaking it is used to decorate straps, cases, bezels, etc.


Divers Watches

Diver’s watches are designed and manufactured especially for divers whose lives depend on the reliability of their watch in the


water. Diver’s watches must meet various standards regarding water resistancy, pressure resistancy, readability in the water, time presetting function (rotating elapsed time bezel), anti-magnetic ability, anti-shock, rust resistancy in salt water, manageability in water, ability to withstand sudden temperature changes, etc.


Dress Watch

A dress watch is an elegantly designed timepiece with a restrained and classy aesthetic, suitable for a black-tie event.

Dual Timer

A watch that measures current local time as well as at least one other time zone. The additional time element may come from a twin


dial, extra hand, subdials, or other means.


Dual Time-Zone

A dual, or multiple time-zone timepiece allows simultaneous display of the time in different time-zones.


Elapsed Time Rotating Bezel

A graduated rotating bezel (see 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.


Electronic (Quartz) Watch

A watch, usually battery-powered, which uses an electric current to cause a quartz oscillator to vibrate, normally 32,768 Hz per second but


sometimes at much higher frequencies. These vibrations are processed by an integrated circuit which transforms the current into impulses. These are fed into a stepping motor which drives a train of gears to move the hands. Some quartz watches have solar cells which take light from any soul, natural or artificial, and transform them into electrical energy. Another form is the Seiko Kinetic (See Kinetic).



The saturated green variety of the Beryl family. Its color is due to minute traces of chromium or sometimes vanadium. Emeralds have a


hardness of 7-8 and a specific gravity of 2.6 – 2.8.



A colored or transparent layer of vitreous material (i.e. a special type of glass) which protects or decorates its metal substrate.


The part of a mechanical calibre which controls the rotation of the wheels and motion of the hands.




Flyback Chronograph

A specific type of chronograph where the ‘stop’, ‘reset’ and ‘start’ functions can performed with a single push, used for recording lap times.

Flyback Hand

A seconds hand on a chronograph that can be used to time laps or to determine finishing times for several competitors in a race. Start


the chronograph, putting both the flyback hand and the regular chronograph seconds hand in motion. To record a lap time or finishing time, stop the flyback hand. After recording the time, push a button and the hand will “fly back” to catch up with the constantly moving elapsed-time hand. Repeat the process to record as many lap times or finishing times as needed.



The ability of certain gemstones to transform invisible light (ultra violet light) into visible light (see Luminescence). Fluorite is such a mineral.


Fluting is a decorative design feature often found on the bezel or sides of a casing.


Gear Train

The system of gears which transmits power from the mainspring to the escapement.




Gold has seduced the world with its beauty, but also because not even acid can alter its natural


properties. An estimated 130,000 tons have been extracted from the earth since prehistoric times, of which 100,000 tons in the twentieth century alone. Gold is a malleable substance (with a hardness of just 2.5) and therefore easy to work with. It can be used in an alloy with other metals, often silver and copper. These alloys increase its resistance and change its color.
Contains: For 750 gold, approximately:

  • Yellow gold: 12.5% silver – 75% pure gold – 12.5% copper
  • Pink gold: 6% silver – 19% copper – 60% pure gold – 10% palladium – 5% nickel
  • Red gold: 5.5 % copper – 94.5% pure gold
  • White gold: 10% copper – 10% palladium – 5% nickel – 75% pure gold
  • Blue gold: an alloy of gold and iron. Heat treatment oxidizes the iron molecules at the surface of the metal, producing the blue color.
  • Green gold: an alloy of gold, silver and copper.
  • Black gold: obtained by means of chemical vapor deposition (similar to PVD) of atoms of gold, carbon and other metals. The black coating is just a few microns thick. Other surface treatments use electrodeposition of rhodium, chromium and very dark impurities.
  • Brown gold: obtained by heat treatment.


Gold Plated (Gilt)

A layer of gold electroplated to a base metal.

Grande Complications

The most complex of mechanical watches featuring an abundance of complications.The


term is normally restricted to mechanical watches. Quartz watches with additional features are usually described as ‘multi-functional’.


Grande Sonnerie

A type of repeater that sounds the hours and quarter hours when the wearer pushes the button.


A type of engraving in which thin lines are interwoven, creating a patterned surface.



A timepiece with a calibre which is hand-wound does not require a battery, however it does require the wearer to wind it manually to work.

Hard Metal

A scratch resistant metal comprised of binding several materials, including titanium and tungsten carbide, which are then pressed


into an extremely hard metal and polished with diamond powder to add brilliance.


Helium Escape Valve

Helium Escape Valve


The art and/or science of measuring time and exploring timepieces.


That part of a watch case to which the strap is attached. Horns come in various shapes and are attached to the case middle.


A watch whose case has a front and back cover.


Impulse Jewel

The jewel-pin that serves as the point of contact between the time-train and the balance wheel. Also called the roller jewel.


A shock-absorber brand used in mechanical watches which helps prevent damage from shocks to the balance pivots. Kif is another well-known brand.

Integrated Bracelet

A watch bracelet that is incorporated into the design of the case.



Synthetic sapphires or rubies that act as bearings for gears in a mechanical watch.
The jewels reduce friction to make the watch


more accurate and longer lasting.


Jumping Hours

System of timekeeping whereby the seconds and minutes are shown by traditional hands but the hour is shown in a dial cutout (often at


12), on the minutes hand reaching 59 minutes, the hour disc under the dial will jump to the next hour.



Karat or K

An indication of the purity of the metal used, expressed in the number of 1/24th of the pure metal used in the alloy. Metals such as gold are


too soft in their pure state use in jewelry, so they are typically made into an alloy with other metals for strength. 24K (equal to 24/24ths) is pure metal. 18K is 18 parts pure metal mixed with 6 parts of other metals. That translates to 18/24=0.750, which is 75% pure, or 750 parts per thousand.



Refers to the Seiko line of Kinetic watches. This innovative technology has a quartz movement that does not use a battery. Movement of your


wrist charges a very efficient capacitor which powers the quartz movement. Once the capacitor is fully charged, mens models will store energy for 724 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 you to a low capacitor charge when the seconds hand starts to move in two second intervals.



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.

Light Emitting Diode (LED)

A digital watch display showing time at the push of a button.

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.


Projections on a watch face to which the watch band or bracelet is attached.

Luminous Hands

Hands made of skeleton form with the opening filled by a luminous material.


Luminous dials first appeared during the Great War when soldiers needed to tell the time in the


dark. Early forms used Zinc Sulphide compound agitated by a radioactive salt. It was painted on hands and was potentially dangerous to those applying it. Its use was banned in the 50’s, since Tritium, a substance with a low radio activity, replaced it. Other methods have been devised. Timex’s ‘Indiglo’ uses electronic luminescence; a button on the side of the case causes a tiny current from the battery to the electrodes and gives off energy in the form of light. Seiko uses fluorescent material on the dial, activated by any exposure to light.



A new-generation luminous substance, used to coat hands and numerals. It stores light which


it then emits in the dark causing the hands and numerals to glow and continue to be visible. Previously, radium salts were used which, because of their too dangerous radioactive properties, were replaced by Tritium and more recently by Super-LumiNova, a non-radioactive aloxide.




This spring is wound to store energy which is subsequently used to power a mechanical watch. This can be wound automatically or


manually depending on the calibre.



A hand-wound mechanical watch. Wound by turning the crown back and forth until resistance is met.


A manufacture is the term used for a watchmaking company which makes every part of their timepieces in-house.

Marine Chronometer

Highly accurate mechanical or electronic timekeeper enclosed in a box (hence the term box chronometer), used for determining the longitude on board ship. Marine chronometers


with mechanical movements are mounted on gimbals so that they remain in the horizontal position is necessary for their precision.



Markers are indications on the dial for each hour point. These can be batons, circles, lines, diamonds, or others depending on the design of the timepiece.

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



A timepiece with a calibre which is mechanical does not require a battery. Mechanical watches can be either manual/hand-wound or automatic.

Mechanical Alarm

A complication where at a specific time, the timepiece will sound an alarm to indicate the time is that set.

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.


Minute Repeater

A minute repeater complication is a high-end mechanical complication, where upon sliding a switch on the side of the timepiece case, the


timepiece will audibly chime the time. This is done in three sets – the first chimes the number of hours 1-12, the second chimes the number of quarter hours passed 1-3 (15 minutes, 30 minutes or 45 minutes), and finally the number of minutes after the quarter hour. For example, a time of 3:22 would be chimed as 3-1-7.


Moonphase Display

A graphic display by means of a specially shaped aperture in the dial to indicate the phase of the moon, i.e. full, new or somewhere


in between. Very popular in the 90’s but losing favour in the second half of the century.


Mother of Pearl

A smooth, shining material incorporated onto the dials of some timepieces, commonly found in the shells of molluscs such as Oysters.


The inner mechanism of a watch that keeps time and moves the watch’s hands, calendar, etc. Movements are either mechanical or quartz.


Natural Pearl

A natural pearl is also called an oriental pearl. This pearl is formed by an oyster, reshwater mussel or other mollusc as a reaction to a tiny


invading object that happened to be caught inside its shell.




Describes a substance produced by a living organism. Pearl, coral and shell are examples of organic substances used in jewellery.

Open/Open-Worked Dial

A timepiece dial where either part or all of the inner workings of the timepiece or visible from the front.



A device that counts the number of strides taken by the wearer by responding to the impact of the wearer’s steps.

Perpetual Calendar

A Perpetual Calendar complication displays the day, date and month with no need for manual adjustment, years, until a leap including leap


year is skipped – the next instance of this is the year 2100.



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.



A synthetic resin that can be used for watch crystal.

Poinçon de Genève (LED)

The Poinçon de Genève is a certificate awarded to timepieces with impeccable finishing and detail, an independent Swiss certification


guaranteeing the horological excellence of a timepiece.


Power Reserve Indicator

A feature that shows when the watch will soon need a new battery or winding. A battery reserve indicator on a quartz watch informs the wearer


when the battery is low. Often this is indicated by the seconds hand moving at two or three-second intervals.



The button on the side of a timepiece to control a chronograph.

Physical Vapour Deposition (PVD)

A coating of titanium nitrate applied in a vacuum and then covered by a coating of 22k gold to obtain a gold colored finish.



A timepiece with a calibre which is battery powered and does not require any manual or automatic winding.

Quartz Crisis

In the 1970s and 1980s, the invention of cheaper quartz timepieces had a huge detrimental effect on mechanical watchmaking. This period is known as the quartz crisis.

Quartz Movement

A movement powered by a quartz crystal to. 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.




Used to describe the split seconds chronograph (see Flyback) which has two seconds hands sitting atop one another. On depression of a


third chronograph button (most have two), the flyback hand will stop in order to measure say, a lap time; repressing this button with cause the flyback hand to flyback(!) to the other seconds hand which has remained in motion.


Roman Numerals

Numbers displayed in Roman convention e.g. I, II, III, IIII*, V, VI, VII, VIII, IX, X, XI, XII.
*Note the use of “the watchmakers’ four”, using


‘IIII’ instead of the traditional ‘IV’ – this is commonly found on timepieces as it provides better aesthetic balance to the dial.


Rose (or pink) Gold

A softly hued gold that contains the same metals as yellow gold but with a higher concentration of copper in the alloy. A popular


color in Europe, rose gold in watches is often seen in retro styling or in tricolor gold versions. Some 18k red gold watches achieve their color from additional copper in the alloy.


Rotating Bezel

A bezel (the ring surrounding the watch face) that can be turned. Different types of rotating bezels perform different timekeeping and


mathematical functions (see elapsed time rotating bezel,” “unidirectional rotating bezel,” “bi-directional rotating bezel” and “slide rule.”)



The part of an automatic (or self-winding) mechanical watch that winds the movement’s mainspring. It is a flat piece of metal, usually


shaped like a semicircle, that swivels on a pivot with the motion of the wearer’s arm.



Sapphire Crystal

A crystal made of synthetic sapphire, a transparent, shatter-resistant, scratch-resistant (9 on the Moh scale) substance.


A sapphire crystal is the material of choice for many watch collectors. The downsides are that sapphire can chip at the edges if they protrude and can shatter.


Screw-Lock Crown

A crown that can be screwed into the case to make the watch watertight.

Second Time-zone Indicator

An additional dial that can be set to the time in another time zone. It lets the wearer keep track of local time and the time in another country simultaneously.


A self-winding timepiece has a calibre wound automatically by the wearer’s everyday movements by use of a rotor.


A timepiece dial where either part or all of the inner workings of the timepiece or visible from the front.

Skeleton Watch

A watch with no dial and only a chapter ring. As much metal is removed as possible and all the remaining parts are decorated with elaborate engravings.

Slide Rule

A feature made famous by Breitling’s Navitimer, allowing the wearer to perform logarithmic calculations by rotating the bezel.


Associated primarily with aviation chronographs.


Solar Powered

A watch that uses solar energy (from any light source) to power the quartz movement.The Citizen >Solar-Tech< models use this


technology and provide a 180 day power reserve, so they are able to run continuously. For more information, click here to go to Citizens Internet Site.


Spring Bars (or Pins)

Spring-loaded bars between the lugs on the case, used to attach a strap or metal bracelet to the case.

Stepping Motor

The part of a quartz movement that moves the gear train, which in turn moves the watch’s hands.


A white and highly reflective precious metal. Sterling silver refers to silver that is 92.5 percent pure, which should be stamped


on the metal, sometimes accompanied by the initials of the designer or the country of orgin as a hallmark. Although less durable than stainless steel and other precious metals, sterling silver is often employed in watches that coordinate or look like sterling silver jewelry. A protective coating may be added to prevent tarnish.



Watches usually come fitted with either leather or rubber straps that close with a buckle or clasp, or a steel bracelet, that also secures with


a clasp. Divers watches are usually fitted with steel bracelets or rubber straps to avoid corrosion.



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.



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.


Swiss Made

As a part of a move towards greater consumer protection and in order to combat fakes in the Far East that claim to be swiss made, the Swiss


federal council in 1993 laid down the rule that a watch has to satisfy before it could be described as swiss made. The movement must be of Swiss origin, and must contain at least 50% swiss parts. The watch must be cased in Switzerland and pass its final inspection in that country.




A scale used on the bezel of a chronograph allowing the wearer to calculate a constant speed. If starting and stopping the


chronograph resulted in a tachymetric indication of 100, then the speed is 100 units.


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 1.


A telemeter determines the distance of an object from the observer by measuring how long it takes sound to travel that distance. Like


a tachymeter (see “tachymeter”), it consists of a stopwatch, or chronograph, and a special scale, usually on the outermost edge of the watch face.



A feature found on some watches, measures the temperature.


A metal that is used for some watch cases and bracelets. Titanium is much stronger and lighter than stainless steel. Titanium is also hypo-allergenic.

Tonneau Watch

A watch shaped like a barrel, with two convex sides.


A device, invented by Breguet in 1801, in which the escapement is mounted in a small revolving cage as a means of overcoming the


effects of gravity on the precision on a mechanical timepiece.



Uni-Directional Rotating Bezel

An elapsed time rotating bezel, often found on divers’ watches, that moves only in a counterclockwise direction. It is designed to


prevent a diver who has unwittingly knocked the bezel off its original position from overestimating his remaining air supply. Because the bezel moves in only one direction, the diver can 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.




Movement of a pendulum or oscillating body between two extreme positions. The balance of a mechanical watch generally makes five


vibrations per second, equivalent to 18,000 vibrations/hour (2.5 Hz). A more accurate mechanical watch makes 10 vibrations per second or 36,000 vibrations/hour (5Hz).
A quartz watch makes 64,000 vibrations per second ( 32 MHz).

An oscillation (“tick-tock”) equals two vibrations (although oscillation is sometimes incorrectly used to refer to a vibration).



Water Resistance

The ability to withstand splashes of water. Terms such as “water resistant to 50 meters” or “water resistant to 200 meters” indicate that


the watch can be worn underwater to various depths.
Water Resistant – light rain or hand washing, but should not be used while swimming or diving.

Water Resistant to 50M (165Ft.) – Suitable for showering or shallow water swimming
Water Resistant to 100M (330Ft.) – Suitable for swimming or snorkeling.
Water Resistant to 150M (500Ft.) – Suitable for snorkeling.
Water Resistant to 200M (660Ft.) – Suitable for skin diving.
Sometimes water-resistance is measured in atmospheres (ATM). An ATM is equal to 10M of water pressure.


Winding Stem

The button on the right side of the watch case used to wind the mainspring. Also called a “crown.”

World Time Dial

A dial, usually on the outer edge of the watch face, that tells the time in up to 24 time zones around the world. The time zones are


represented by the names of cities printed on the bezel or dial. The wearer reads the hour in a particular time zone by looking at the scale next to the city that the hour hand is pointing to. The minutes are read as normal. Watches with this feature are called “world timers.”



Yacht Timer

A countdown timer (see “countdown timer”) that sounds warning signals during the countdown to a boat race.

Yellow Gold

The traditionally popular gold used in all gold, gold and stainless steel, or other precious metal combinations. Yellow gold watches may


be found in 14k or, as found from most European manufacturers, 18k.




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).


Circular belt with the ecliptic in the middle containing the twelve constellations through which the sun seems to pass in the course of a year.