Watchmaker Glossary

Watchmaking Glossary


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First electronic watch controlled by a tuning fork, launched in 1960.


Time indication and other data. The display can be done either by hands moving on a dial (analog display), or by numbers appearing in one (or more) window(s) (digital or digital display); these numbers can be supplemented by alphabetical indications (alphanumeric display) or by any other sign. Example: 12.05 LU 12.3 = 12 hours, 5 minutes, Monday March 12. These displays can be produced by mechanical and/or electronic means.


Indicator organ formed of a piece of metal, generally thin and light, of very diverse shapes, which moves on a dial or a divided limb. Watches usually have three hands to indicate hours, minutes and seconds.


Name given to the teeth of a pinion.


Organ against which air friction moderates the speed of a mobile, such as the arm of a gravity escapement.

Fitting Action of adjusting the period of a pendulum by lengthening or shortening this oscillator.

Movement of a pendulum or an oscillating organ, limited by two consecutive extreme positions. The balance of a mechanical watch generally makes five vibrations per second, or 18,000 per hour. The oscillation ("tick-tock") has two alternations (the word oscillation is sometimes incorrectly used to designate the alternation).

Shock absorber

Elastic bearing which aims, in the watch, to absorb shocks received by the pivots of the balance axis.


Centerpiece of the exhaust, in steel or brass, so named because of its shape, which recalls the anchor of ships.

Universal astronomical ring

Sundial adjustable according to different latitudes.

Essen Ring

First truly precise quartz oscillator, used for observatory quartz clocks.


Standardized designation granted to watches capable of withstanding an accidental fall from a height of 1 m onto a hard surface without adverse consequences, thus meeting criteria rigorously defined by ISO (International Organization for Standardization, founded in Geneva in 1947). ).


We call appliques the hour numerals or signs cut out of metal plates and then glued or riveted to the dial.


Laminated spring used to transmit driving force in some American console clocks.


In watchmaking, term synonymous with axis (eg: barrel shaft): in general it is a cylindrical body on which a toothed wheel is fixed which it rotates.



Flexible rod of steel or wood which is used to tension a gut rope or horsehair in order to move a part on the lathe.


Operation which consists of tensioning (cocking) the spring of a barrel, and which is carried out either manually (using the crown or a key) or automatically (by the rotor).


Device which limits the cocking of the barrel, by reducing its angular travel. The best known of these mechanisms is the so-called “Maltese cross” stop.


Finish the gear tooth profile by milling.


Set of parts that make up the escapement (escape wheel, lever, plate) and which transform the rotary movement of the gear train into the back and forth of the balance or pendulum.


In ancient times, the most important instrument for astronomy, navigation and time measurement; he measured the height of the stars.


Animated character or various object, for example a windmill or a seesaw.


Watch whose spring is wound by the movement of the wearer. Many devices have been made since the end of the 18th century. However, it is the so-called "rotor" device, which has become widespread in wristwatches since the 1940s. The origin of this system can be found in a document from the French Academy of Sciences, dated December 23, 1778, which describes a piece deposited by the Liège watchmaker Hubert Sarton. It is currently the oldest documented descriptive text of an automatic system.


Term synonymous with tree. Watchmakers usually say, for example, balance axis.

Balance axis

All the axes are shafts, with the exception of that of the balance wheel which is called an axis.




Mobile part, generally circular, which oscillates on its axis of rotation. The hairspring which is coupled to it gives it a back and forth movement, dividing time into strictly equal portions. Each of these back and forth (“tick-tocks”) is called oscillation. The oscillation is divided into two alternations.

Oscillator balance

Originally a foliot, then a circle which regulates the speed of the escapement; associated with a spiral spring from 1675.

“Dumbbell” balancer

Oscillating bridge equipped with a mass at each of its ends, used in watches before the invention of the sprung balance.


Thin cylindrical case - inside which the mainspring is housed - whose toothed edge drives the watch's gear train.

Weight barrel

Barrel on which a rope, wire or gut cord wound and terminated by a weight drives the cogs of a clock.

Spring barrel

Barrel containing a mainspring which transmits the driving force.

Toothed barrel

As opposed to the smooth barrel connected to the fusee by a chain or a gut rope, the toothed barrel is fixed on a wheel which meshes with the rest of the gear train.

Suspended barrel

Said of a toothed barrel fixed only in the movement by its upper part.


Small metal rod fixed between the horns of the box and on which the bracelet is adapted.


Texturally, turn a box to give it the shape of a “basin” by rounding the bottom of the box with a chisel.


Designates, inside a watch case, the part on which the movement rests. In chiming watches, Julien Le Roy imagined removing this frame and replacing it with a small gold metal ring separating the dial from the front plate. The space thus created makes it possible to accommodate a significant part of the parts of the striking mechanism. All of the parts thus housed under the dial have, by extension of the term, been called "framing".


Number of ticks obtained in a given time. A floor clock “beats the second”, that is to say once every second.


Ring of various shapes used to hang the watch.


Blade made of two metals with different expansion coefficients, used in the manufacture of compensated balance wheels.


See Draft

Rolling white

Movement in working order, ready to receive finishing work (ironing, adjustment, adjustment) and finishing work (gilding, signature).

Watch box or case

Box used to protect the watch movement against dust, humidity and shock. It still makes the watch look as attractive as possible, influenced by fashion and the taste of buyers.

Hourly ball

Signal used in the past to indicate the time using a ball which slid along a mast planted at the top of a tower.


Radius of a circular pendulum.


Small pliers that allow the watchmaker to handle delicate parts.


Pivot polishing process.


Polishing file used to give shine to metals, such as steel or copper.

Walking bulletin

Official document established by various astronomical and chronometric observatories and giving the name "chronometers" to a watch which has successfully undergone a series of very severe tests relating to its precision (day rate, thermal coefficient, etc.).


Fixed organ intended to limit the travel of a mobile organ. The angular movements of the anchor are limited by stops.

Arming capstan

Large medieval bell tower and belfry clocks were wound using a capstan or spoke wheel attached to one end of the barrel.

Dust cover

Small metal cover used to protect the movement of watches at the time when it was easy, by tilting them, to take them out of their box.


Indicator body, metal or other part which carries various indications, hours, minutes and seconds for usual watches and clocks. Indications are given by numbers, divisions or signs (indexes) of various shapes.

Dial 13 pieces

dial made up of 12 enameled cartridges bearing the hour numerals arranged around a thirteenth central piece, also enameled and often decorated.

Calendar dial

Special dial giving calendar indications such as day of the week, date, month, year and religious holidays.

Height dial

Sundial indicating, according to the length of the shadow cast by the gnomon, the height of the sun in the sky.

Horizontal dial

Fixed sundial with horizontal graduation, for example, ordinary garden sundial.

Vertical dial

Sundial with vertical graduations.


Term designating all the mechanisms (strike, dates, timer) placed between the dial and the front plate.


According to the definition given by JC Nicolet, "the cage is the frame or chassis inside which all the parts of the watch movement are housed. The cage of clocks is made up of 2 plates while that of watches is made up of a plate and several elements screwed onto it, called bridges".


Originally, a synonym for dimension for a watch movement. Today, designates a type of movement (men's caliber, automatic caliber). Followed by the manufacturer's mark, designates the provenance.

Lépine Caliber

Watch movement in which all the wheels are under a cock or bridges.

Hourly canon

Time signal given by the detonation of a cannon.


Designates in watchmaking the end of a rod with a square section. In general, the squares are used for reassembly. There are two types: male squares, filed on a cylindrical part, female squares, formed in a hole.


Middle part of the watch case in which the movement is placed.


Rotating device similar to the tourbillon, but more robust.

Time center

High-precision installation (most often today it is an electronic quartz clock or an atomic clock), which delivers pulses to a series of secondary clocks and which sometimes itself controls a system public time distribution.


Watch movement (dial and hands not included) of which all or part of the spare parts are not assembled.


Small chain, similar in miniature to a bicycle chain which replaced the gut rope used in primitive watches to connect the fusee to the barrel.


Refers to a surface dug with a chisel in the field of a metal plate, to receive the enamel.

Chaperone or counting wheel

Wheel whose profile, consisting of alternating hollows and bumps, regulates the striking of the hours.

Lost hinges

This term refers to invisible hinges for watch cases. Lépine was the first to create watch boxes with “lost hinges”.


To “hunt” a stone, in watchmaking, is to push it into its housing by pressure. Due to its ease of execution, driving has replaced crimping.


Friction pinion which drives the timer and which supports the minute hand.

Flat chassis

Horizontal frame of a modern bell tower clock.


Metal ring in which the pierced ruby ​​which serves as a bearing for the pivot is fixed.

Chainring dowel

Part through which certain oscillators receive their impulses.


Device that allows the watchmaker to quickly test the performance of a watch.


Watch or device comprising two independent time systems: one gives the time, the other records short times. Seconds, minutes and even hour counters are started and stopped on command. They thus make it possible to directly measure the precise duration of a phenomenon. Do not confuse with counter or stopwatch.


Watch having passed - in official offices - a performance test for its precision. The requirements are very high: a few seconds per day in the most difficult temperature conditions (for mechanical chronometers) and positions usually encountered.

Marine chronometer

High precision timepiece (mechanical or electronic) enclosed in a box, used on ships to determine longitude. Marine chronometers with mechanical movements are mounted on gimbals to ensure the horizontal position necessary for their precision.


Water clock.


Small lever in the shape of a beak or comma which penetrates, under the action of a spring, into the teeth of a wheel, so as to prevent it from going backwards.

Sundial compass

Sundial which, oriented north-south, indicates, according to the angle formed by the shadow of the gnomon, the position of the sun in the sky.


In watchmaking, it is a generic term for chronographs.

Thermal compensator

Device generally made using two metals expanding differently, intended to correct the effects of temperature on the operation of watches and clocks.

Auxiliary compensator

Device added to the compensated balances of chronometers to correct the secondary error, that is to say the effects of changes at temperatures intermediate to those actually compensated.


Layer of enamel deposited on the back of an enameled part, for example, on the back of a watch or clock dial, or inside a case whose bottom is enameled.


Watch balance bridge.

pendulum cock

Ornate balance bridge attached to the lower plate of a watch and serving as a bearing for the balance axis.


Metal washer used by French watchmakers in place of the counter-pivot stone.


In certain clocks, a cord which, once pulled, triggers the chime of the elapsed hour, or even that of the quarter.

Terminal curve

Ends of the hairspring curved towards the center to improve isochronism. Invented by Breguet and perfected by Phillips. By extension, we often speak of a “Phillips curve” or a “Breguet” hairspring.


Knurled button located on the outside of the watch case and used both for winding the spring and for setting the time of the watch or updating the date of the calendar if it has one.


Pivot hole made directly in the brass plate, where a steel pivot of the wheel train or the escapement moves, which was not previously without posing friction problems, which were only solved by Nicols Fatio , who had the idea of ​​using rubies as cushions.

Compensate for

Correct an error source effect, such as temperature differences, on the operation of watches.


Instrument used to record time intervals (durations, short times), without indicating the time.


Undrilled precious stone used as a cushion and against which the pivot of the balance axis abuts.


Knurled button located on the outside of the watch and used to wind the spring. Also used to set the time and update the calendar.

Rack or rake

Straight or curved arm equipped with teeth.


In a watch case, the double bottom is called a bowl, often engraved with inscriptions or a signature.


Small springs invented by Huygens, intended to improve the isochronism of the pendulum's oscillations.


In an anchor escapement, a small metal pin that prevents accidental movement of the fork.


System established by a decree of the Convention of 1792 according to which the day was divided into two times 5 hours of one hundred minutes each lasting 100 seconds.


Generic term which refers to all turning, drilling, tapping and milling operations, whether carried out by hand or on automatic or semi-automatic machines.


Lever which maintains then triggers a mechanism and which, therefore, regulates its movement.

Spring trigger

Some triggers are mounted on pivots, others are on a leaf spring.


Variation of rate of a timepiece.

Tuning fork

Small metal part with two branches whose vibrations, maintained by an electromagnet, activate a pawl which pushes, tooth by tooth, 300 to 720 times per second, the first wheel of the cog.

Low power diode or photoemitting diode (LED = Light Emitting Diode)

Dotted light source used for displaying numbers on electronic digital watches.

It operates on call using a push button.


Machine tool accessory intended to divide the circumference of wheels and cut the necessary number of teeth.

Mercury gilding

Application of a gold amalgam to a metal support, followed by light heating to remove the mercury. Process now supplanted by electrolysis gilding.


Groove made in the bezel of a watch case to secure the glass.


Specialized box turner who worked on a "Dubail" pantograph lathe allowing the same box shapes to be reproduced in series.


Set of unassembled parts of the movement (platinum, bridges, gear train, winding and time setting mechanism, adjustment rack) and marketed in this form. However, the following are not part of the outline: the regulating organs, the escapement, the spring.

Exhaust The escapement counts and maintains the oscillations of the balance wheel.
There are two types of exhaust:
* free = anchor, relaxation, …

* at rubbing rest = cylinder, pendulum balance, etc.

Anchor escapement

Watch escapement which gives excellent results and which is reminiscent of the recoil lever escapement, with the difference that it is free.

Recoil lever escapement

Regulating mechanism for pendulum clocks, invented around 1670, which greatly improved timekeeping. In Europe, the fork stick was called a recoil anchor because of its shape.

Peg exhaust

Anchor escapement used in watches or clocks and in which round or D-shaped vanes, made of steel or ruby, receive the impulse from the teeth of the escapement wheel. In inexpensive watches, the ruby ​​palettes are replaced by hardened steel pegs.

Permanent contact exhaust

Escapement in which one tooth of the escape wheel is in constant contact with the balance wheel, as in the cylinder escapement. This escapement is not free.

Quick-shot exhaust

Exhaust in which the ticking is faster than normal.

Cylinder exhaust

Escapement in which the balance axis is part of a cylinder actuated by the teeth of the escape wheel.

Expansion exhaust

Free escape that uses a trigger to cause the escape wheel to stop.

Gravity exhaust

Escapement in which the impulse is provided by a lever, generally under the action of gravity, in the form of a winder.

Recoil exhaust

Elaborate meeting wheel escapement in which two vertical balances oscillate in opposite directions and cross each other.

Exhaust at rest

Recoilless escapement where the escape wheel acts, through the tips of its teeth, on the inclined beaks of the anchor.

Encounter wheel exhaust

Escapement used in early mechanical clocks and which persisted for a very long time. It consists of the meeting wheel and a tree (the rod) which carries the foliot and two paddles.

Ormskirk Exhaust

Exhaust equipped with two escape wheels. Its name comes from Ormskirk, Lancashire where it was invented.

Duplex exhaust

Escapement in which the escape wheel has a double row of teeth, or provided with two escape wheels. Originally used for high precision watches, then inexpensive models.

Horizontal exhaust

Another term used for the cylinder escapement.

Free exhaust

An escapement which has no contact with the balance or pendulum except during disengagement and impulse, for example in anchor and detent escapements.

Magnetic escapement

Escapement in which the oscillator and the escape wheel are connected by a magnetic device.

Grasshopper exhaust

Ingenious exhaust that required no oiling, invented by John Harrison.


Apparent movement of the Sun around the Earth.

Liquid crystal display (LCD = Liquid Cristal Display)

In electronic digital watches, screen on which you can constantly read the time indicated by dark numbers or letters standing out against a light background (or vice versa).

Analog screen

Screen imitating the movement of a natural timepiece, such as that of the Sun, and reminiscent of a classic clock dial with moving hands.

Digital screen

Screen on which the time is indicated in numbers: 07 16 42

Adjustment nut

Nut which, mounted under the lens of a pendulum, allows this organ to be raised or lowered to adjust the period of the pendulum.


The art of painting a decorative pattern on the back of a clock casing glass panel.


Alloy with practically zero thermo-elastic coefficient within normal temperature limits and used to compensate for the effects of temperature on the hairsprings.


Action of introducing and fixing the movement in its case


Set of clockwork stones used in pivot holes to reduce friction. A normal gem setting includes 15 to 19 rubies.


Refers to a wheel whose teeth penetrate the wings of a pinion to make it move.

Equation of time

Difference between true time (recorded on a sundial) and average time (recorded on a clock).


Tool used by the watchmaker to wind and insert the mainspring into its barrel.


Method of manufacturing the watch and/or movement consisting of assembling the various constituent elements. It generally includes the following operations: reception, control and storage of blanks, regulating parts, as well as other movement supplies and clothing; reassembly; setting; installation of the dial and hands; nesting; final inspection, before packaging and shipping.


Hardened steel matrix which gives its shape to a part or a hole.


Who doesn't let water in. Waterproof box, whose seals and closures are constructed to prevent the introduction of humidity.

Fake plate

This name refers to the purely decorative plate on which the dials of clocks and watches were formerly fixed. Subsequently, the sheet metal on which pendulum dials are often fixed continued to be called a false plate.


Set of operations which transform the blank (spare parts) into rolling blank (movement in working order).


Sculpted ornament which completes the crowning of a column or any other part of a movement or the casing of a clock.

Flyback or Return in flight

This function has its origins in the field of aviation. By simply pressing a pusher, the “Flying Return” function returns the chronograph second hand to zero. She then instantly resumes her course for a new count.


Oscillating crosspiece, each arm of which supports a mass, used in the first mechanical clocks as a regulating organ.


We call “function” any information delivered by a timepiece. We would say of a watch which gives the hour, minute and second, day, date and month that it has 6 functions. So-called “complicated” watches multiply the additional indications.


Thin layer of transparent enamel deposited on the surface of dials and enamels.

Whip of watches with dead seconds

Small rod, carried by a special gear, the end of which is engaged in the wings of the exhaust pinion; released every second, the whip makes a complete revolution and communicates its movement to the seconds hand which thus advances one step per second.


In watches as in pendulums, part of the lever which ensures the connection between the escapement and the pendulum rod or the balance wheel.


Detached pieces. These are the constituent parts intended either for the production of the watch or for its repair. In the latter case, we speak of “supply of dressing”.


One of the first instruments for cutting wheels and pinions, used in watchmaking factories, and resembling the fruit of the same name.


Unit of measurement which translates the number of oscillations or vibrations per second and which is expressed in Hertz; it is generally supplemented, for pendulums and sprung balance watches, by the indication of the number of vibrations per hour (eg: 2.5 Hz = 18,000 vibrations per hour = 9,000 oscillations per hour).


Conical shaped part, connected to the barrel by a hose or by a chain, and intended to regulate the force of the spring.

Chain guard

In watches equipped with a fusee, it is a small lever which, raised by the chain, blocks the fusee at the end of winding. The chain guard is a stopper.


This name, recently reserved for high-precision instruments used for the measurement and "conservation" of time, formerly applied to any time instrument, such as clepsydra, hourglass, sundial, etc.


Thin plate of glass or a transparent synthetic product, which protects the dial of the watch, clocks, etc.


Style in which the shadow is projected on a sundial.


In striking watches, these are metal blades, generally steel, arranged around the movement and on which the hammers strike. Gongs replaced gongs in striking watches at the end of the 19th century, which made it possible to make flatter watches.

Great ringtone

Automatically chimes the hours and quarters.


In watchmaking, it is a device for correcting the effects of temperature, applied to clocks, more rarely to watches. It is made up of rods, some of which are made of steel, the others of brass, bronze or zinc.

Ticket office

Small opening. Window watch, in which the dial is provided with openings under which various indications appear: dates, hours, etc.


Engraving designs on the case of a watch using a machine called a “guilloche lathe”.

Clothing or dressing

Set of spare parts (case, dial, hands, crystal, crown, etc.) which, by covering the movement, contribute to giving its definitive and utilitarian appearance to the watch.


Sundial indicating average time, i.e. the same time as a clock.

Hertz or Hz

Unit of frequency equal to one cycle per second. A royal or seconds pendulum oscillates for example at 0.5 Hz, its period is 2 seconds.

Mean solar time

Time indicated by a sundial and corrected by the equation of time so that the hours have equal duration.

True time

Time indicated by a sundial without correction by the equation of time.

Temporary time

Division of the light period of a day into a given number of hours and that of darkness into an equal number of hours. System commonly adopted before the introduction of the mechanical clock.


Generic term attributed to any time instrument (gnomon, clepsydra, sundial, hourglass, mechanical clock) and which common usage today reserves for a non-portable time mechanism often provided with a strike (pendulum or floor clock) , operating only in a fixed position. In a time distribution system, we usually speak of a master clock (the central mechanism which delivers the pulses) and a secondary clock (the one which receives them and which only serves to indicate the time).

Rack clock

Clock which, driven by its own weight, slides along a rectilinear rack.

Bell tower clock

Monumental public clock also called a belfry clock.

Master clock or master clock

A clock that remotely operates other secondary clocks or dials.

Marine clock

Term used until the 19th century to designate marine chronometers.


Science of timekeeping.


Cavity made in the pads to place a drop of oil.


Motion communicated for a fraction of the time to keep the oscillator moving.


Form of shock absorber most frequently used in motors today.


Iron-nickel alloy which, having a very low coefficient of expansion, does not change in length following temperature variations. It is used for the rods of precision pendulums...


Which occurs at equal time intervals. The oscillations of a pendulum or a sprung balance are isochronous when their duration is independent of the amplitude.

Jacquemart First form of clock automaton, representing a character striking a bell.

Jaquemarts, "hammering" automata operated by a bell ringer, then by a mechanism connected to a clock, striking a bell, Origin: Orient (period of the Crusades), After the 5th century: decline of the spectacle fading in the face of the usefulness of public clocks (dial visible from afar) and indoor clocks, Statistics (in France): number: around 20, Figures: generally in oak, polychrome, sometimes covered with tinplate, some in copper (Dijon) or bronze (thin wall , Cambrai), Sizes: Romans-sur-Isère 2.60 m, Cambrai 2.50 m, Thann 1.18 m, Auffay 1 m, Lyon 40 cm, Number of statuettes: Auffay, Feurs, Molsheim, Thann, Cambrai 2 ; Aigueperse, Clermont-Ferrand, Compiègne, Lambese, Montbard, Befeld 3; Avignon, Lyon, Mondidier, Moulins, Dijon 4. Types: Avignon, Beaumont-le-Roger, Benfeld, Besançon, Lavaur, Moulins, etc. : “man-at-arms”; Molsheim: “cherub wife and child”: Lyon: “Guignol and Gnafron”; Clermont-Ferrand: “Mars”, “Time”, “Wildlife”: Cambrai; “Moor”: Benfeld, Thann: “Death”; Dijon: “Jacquemart, Jaquette, Jacquelinet, Jacquelinette”: St-Omer: “Mathurin”: Graveson: “Beluguet”,


Mass attached to the end of the pendulum rod.


Part of the anchor on which the escape wheel abuts in order to obtain the impulse necessary to maintain the oscillations. We distinguish between the entry lift and the exit lift.

Lever In a striking mechanism, the trigger lever, controlled by the timer, is intended to start the process at a precise moment,

opposes the stop lever, designed on the contrary to stop it when all the shots have been struck.


Refers to an escapement which is only in contact with the balance at the moment of impulsion and release. The additional oscillation of the balance wheel is therefore free.

Line and thumb

Old unit of measurement still often used in watchmaking. The line is 2.256 mm.


Spiral-shaped cam with notches which adjust the hour, quarter and half hour strikes.

Watch bezel

Ring fitted to the middle and which carries the glass.


In the Swiss watch industry, this name refers to factories that make the watch almost entirely, as opposed to finishing workshops in which only winding, adjustment, fitting of the hands and casing are carried out.


Operation of a timepiece, evaluated according to its regularity. The advance or delay it takes in 24 hours compared to a reference time standard is called diurnal rate.

Weights or weights

Small metal parts placed on the edge of the balance wheel and used to adjust the advance and delay when there is no adjustment rack, in particular for chronometers.


Large imaginary circle passing through the two earth poles.


It is very precisely, according to René Béguin, an auxiliary mechanism establishing the speed ratio between the minute hand and the hour hand and composed of 3 elements: the roadway, the timer wheel with its pinion and the wheel hours.

Setting up the barrel

Prior tension of the spring housed in the barrel connected to a fusee.


In watchmaking, the mechanism of watches and clocks is called a movement.


Device which slows down, which regulates. When striking watches and clocks, it is necessary to moderate the speed of certain gears. This is done with finned steering wheels, ball or centrifugal force regulators, or even escapements: with anchor for certain bells (invention by Julien Le Roy in 1755) with rod for alarm bells.


Before being used in electronic watchmaking, where it designates the entire movement, the module originally constituted, in mechanical watchmaking, an easily interchangeable sub-assembly (display, gear train, motor, etc.).

Automatic watch also called perpetual

Mechanical watch which uses the principle of terrestrial attraction to wind itself by the movements of the arm alone, which turn a rotor which transmits the energy thus accumulated to the mainspring.

“Toc” watch

Watch in which a hammer strikes inside the case and allows you to know the time by touch. Imagined around 1750 by Julien Le Roy.

Figurative watch

Watch whose case adopts a given shape, that of a beetle, a violin, a cross...

Perpetual watch

First commercial automatic watch, invented by Breguet.

Synchronous motor

Electric motor that runs in synchronization with the network frequency.


Duly assembled assembly of the main organs and mechanisms which make up the watch, namely: the winding and time-setting mechanism, the mainspring, the gear train, the escapement and the regulating organ or regulating organs (spring balance) . "Anatomically", the movement is made up of the blank, the regulating parts and the other supplies (spring, stones, pivots, pinions, screws, shock absorbers, etc.). The watch is said to be "complete" when the movement has been covered with clothing.

Paris Movement

Specifically French movement, with two bodies, cylindrical in shape, suitable for cartels and mantel clocks.


Hand-held protractor which allows you to determine the time at night by observing the position of the Great Bear.


Pot-bellied watch, similar to an onion, produced in the 18th century by French watch manufacturers.


Name given to the planetary, mechanism representing the movement of the planets, after Charles, fourth Earl of Orrery.

Regulating bodies

The balance wheel and the hairspring constitute the regulating organs of the mechanical watch. These elements count the time. In a clock, the regulating organ is the pendulum. In electronic watches, this can be a motor balancer, a sound resonator or a quartz crystal.

(or regulators)

Device which, like the pendulum or the balance wheel, generates oscillations which divide time into equal units.

Quartz oscillator

Regulatory organ of a clock or quartz watch.


It could be the two levers of the rod against which the meeting wheel abuts, thus maintaining the oscillations of the foliot, as well as the parts of the anchor (in steel, ruby ​​or sapphire) which come into play. contact with the escape wheel.


Based on "a simple set of levers proportioned so that one end of the system exactly reproduces the movements of the other end by reducing or amplifying them", the pantograph is defined, according to JC Nicolet, as a machine allowing "of effector of shaped hollows in the plates of watches, by reproduction of a model called "patronne". The "Dubail" copying lathe is only an industrial version.


First watch shock absorber, invented by Breguet.

Regulating parts

Set of parts including the regulating organs (spring balance) and the escapement.


Part of the pocket watch which receives the winding crown and the ring which allows it to be hung; the invention of the pendant winder, which eliminated the separate winding key, was the work of Thomas Perst, in 1820, and was improved by Louis Audemars in 1838, but it is Adrien Philippe who we owe the current system of winding, developed in 1842.


This name, formerly reserved for timepieces regulated by a pendulum, now applies, whatever the particularities of the clock mechanism, to any timepiece of large volume intended to be placed or hung.

Grill pendulum

Pendulum made of several rods of different metals (steel and brass) whose thermal coefficient of expansion makes it possible to maintain the length of the oscillator at a constant level despite variations in temperature.

Mercury or Graham pendulum

Pendulum in which a hollow cylinder containing mercury serves as a lens and compensates for the effects of temperature variations.

Bubble Pendulum

Pendulum equipped with a magnetic lens oscillating in a metal coil, invented by Mr. Favre Bulle around 1920.

Seconds pendulum

Pendulum approximately one meter long beating the second, invented after around 1670.

Eureka Pendulum

Very large circular balance wheel used in some early electric clocks.

Sympathetic pendulum

Clock which resets and regulates a special watch during the night, invented by Breguet.

Torsion pendulum

This oscillator, used in medium-sized clocks, has properties similar to those of the pendulum itself, from which it only differs in fact by its much longer period. It consists of a mass suspended from a wire or metal ribbon, around which the system rotates alternately in one direction and the other. It notably equips so-called “400 day” clocks.


Time interval determined by the regular and repetitive return of a phenomenon.


Old term, used by Bréguet to designate a self-winding watch.

Moon Phases

Indicates the state of the moon: new, waxing, waning or full


Small toothed piece of steel, usually driven by a larger brass wheel.

Lantern or spindle pinion

Pinion whose teeth are formed by small cylinders or spindles, used in place of the toothed pinion.


Each of the 4 columns which connect the two plates of a clock, the whole forming the cage.


Bushing, counter-pivot, paddle, used to reduce friction. Generally made of synthetic material, with the exception of precious or semi-precious stones (ruby, sapphire, garnet) which can be used in the movements of luxury watches.


In watchmaking, the term pirouette indicates that a gear has been placed between the escapement and the balance wheel. This device makes it possible to increase the extent of the balance's arcs, in other words its amplitude. Huygens' first verge escapement fitted with a hairspring was a pirouette one, as was Sully's.


End of an axle rotating in the bearing which serves as its support.


Safety device which, in the anchor escapement, limits the movement of the fork.


Base part on which all the other parts of the movement are assembled (part of the blank).

Engine weights

These are weights used as a driving force, example: weight clocks.


Complementary part attached to the plate forming the frame or cage of the movement; the other parts are assembled inside the cage (part of the blank).


Watch case projection which, through its pulsations, allows you to know the time on demand and silently.


Order number of each day in the month: February 10. Calendar watch: watch which indicates in apertures the date, the month, sometimes the year and the moon phases. Perpetual calendar: watch which indicates, in addition to the date, leap years.

Perpetual calendar

We thus designate watches and clocks whose date of the month automatically changes at the end of the month, whether the months have 28,29,31,31 days, taking into account leap years.


Toothed sector used in certain passing ringing mechanisms which do not have a counting wheel (chaperone).


Device allowing the display of several successive times measured from the same origin, the reading time being able to be caught up without disturbing the measurement. Equivalent term: intermediate time.


Adjustment organ which allows the daytime running of the watch to be corrected by adjusting the length of the hairspring.


All operations intended to ensure proper functioning of the watch. There are several types of adjustments depending on the precision sought (adjustment in different positions, adjustment at temperatures).


Precision floor clock, generally equipped with a special dial whose hands are not coaxial.


Setting up the various organs that make up the movement. Operations (formerly entirely manual) are now highly automated. The human element, mainly for controls, is however always essential.


Mechanism which transmits, via the input and output pallets, a constant force to the balance or pendulum.

Automatic winder

Automatic winding of the mainspring of a wristwatch via a steering wheel which turns according to the movements of the wearer's arm.

Auxiliary winder

Mechanism used to keep a time instrument running during the winding operation.

Equality winder

Device allowing, by means of a main spring, to arm a secondary spring or to raise a weight at regular and relatively short time intervals. Thanks to this device, it is possible to use as a driving force the section of a mainspring which delivers a practically constant force to the gear of a watch or a clock. The equality winder also allows weights to be used as the driving force of a mantel clock or desk regulator. The weights being raised at regular intervals by the main spring, it is no longer necessary to have a great length for their travel.


Chiming watch, which indicates the hours with a chime when a pusher or lock is activated. There are several kinds of repeaters: quarter repeater, which sounds a low stroke for the hours and two strokes for each quarter, one low and the other high; five-minute repeater, which sounds the hours, quarters and five minutes in addition to a quarter; minute repeater, which sounds the hours, quarters and minutes; grande sonnerie, which strikes the hours and quarters in passing (automatically) and repeats the entire chime by pressing a pusher; chime repetition, where the quarters are sounded on three or four timbres giving different tones.


Moment during which the escape wheel no longer transmits energy to the regulating organ.

Power reserve (indication of)

Display on the dial allowing you to visually know &endash; in hours or days &endash; the winding condition of the watch.

Hipp contact spring

Contact used in certain electric pendulum clocks to regulate the amplitudes of the pendulum oscillations.

Main spring

A spirally wound spring inside the barrel, used to produce motive force in place of a weight.


Spring whose function is to return an organ to a specific position; it is for example used to prevent the hammer of a bell from resting on the gong.

Spiral spring

Hairspring attached by its ends to the circular balance and the cock.


Action and result of refinishing, that is to say, repairing a watch, putting it back into working order.


Watchmaker specializing in watch repair.


Toothed wheel that a ratchet forces to turn in one direction.


Half disc of heavy metal that the energy coming from each movement of the arm rotates freely inside the case of the automatic watch. Its weight tends to always put it back vertically. Multiplied by an ad hoc device, its rotations continually arm the spring.


Set of toothed wheels and pinions of the watch.

Ringing gear

Set of wheels and pinions that operate the bell.


Toothed driving wheel riveted to a pinion. The same shaft is connected to a large number of wheels and gears.

Account wheel

See "chaperone".

escape wheel

Toothed wheel of a timepiece whose operation is regulated by the escapement.

Singing wheel

Wheel whose teeth are cut perpendicularly to the side, as in corner wheels.

Meeting or crown wheel

The escape wheel of a meeting wheel and verge escapement, provided with pointed teeth on one side, and parallel to a shaft (called the verge).

Minute wheel

Toothed wheel whose shaft turns the minute hand.

Driving wheel

Main driving wheel of a clock.

Wolf Tooth Wheel

Wheel whose teeth are inclined like those of a ratchet. Wolf-toothed wheels were used by Lépine for some of his watches. Some winding wheels of the first pendant-wound watches were wolf-toothed.


All pivot pins subject to friction are fitted with stones, generally synthetic rubies, which protect them against excessive wear.

Eighth or time wheel (clockwork) The eight-wheel is located between the center wheel and the barrel and
between the star wheel and the barrel (also called time wheel) and

allows the clock to run eight times longer


Device which measures time intervals by the flow of sand from one bulb to another.

Bar of soap

Pocket watch whose box has funds on each side. The one that covers the dial is operated by a spring mechanism called "secret".


Who jumps. Jumping hour watch: watch whose hours appear in a window on the dial; the time change occurs suddenly, with a jump.

Long necklace

Small lever held down by a spring, intended to keep a wheel in the same position between two movements.


Primitive graduated sundial inside a hollowed-out globe.

“Scratch dial”

Rudimentary vertical sundial inscribed on the southern porch of a church several centuries ago, indicating the times of religious services. Sometimes called "Mass dial".


Pendulum, clock or dial operated by a master clock.


Base unit of time corresponding to the 86,400th part of the mean solar day. This is given by the duration of rotation of an ideal Earth, describing a circle around the sun in one year, at constant speed and in the plane of the equator. After the Second World War, atomic clocks became so precise that they were able to highlight the irregularities, although infinitesimal (a few hundredths of a second per year), in the duration of the Earth's rotation on itself. It was then decided to redefine the reference standard, which the Thirteenth General Conference on Weights and Measures did in 1967, in the following terms: "The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. Conventionally, the second is notably subdivided into tenths, hundredths, thousandths (milli-), millionths (micro-), billionths (nano-) and trillionths (pico-seconds).

Second at center

When the second hand is in the center.

Current second

This is sometimes called the second hand.

Dead second

When the second hand remains stationary between two seconds. It is also said that it “beats the second”. Bréguet used the term “second in one go”.

Independent second

Invention of Moïse Pouzait, when the mechanism operating the deadbeat seconds hand is independent of the movement of the watch itself.


This designates the annular part of the balance of a watch or a chronometer.


Technique which consists of placing a pierced stone at the exact location of the pivot hole of a mobile and which, due to its difficulty of execution, was abandoned from 1935 in favor of "hunting".


Device that rings on demand or automatically to mark the hours or to wake up at a certain time (see repetition).

Rake ringer

Ringing controlled by a curved rake which falls on a snail. This ringtone does not count down.


Small spring wound in a spiral and constituting with the balance the regulating organ of the mechanical watch. It returns the balance to its starting position at the end of each alternation.

Bent flat hairspring

Hairspring whose outer turn is wound concentrically and raised relative to the rest of the spring. Sometimes referred to as a “Breguet hairspring”. It allowed the spring to develop steadily as it expanded and concentrated.

Armillary sphere

Replica of Ptolemy's universe, with the earth placed in the center. Assembly of circles and rings (armilles) used to represent the celestial equator, the tropics, the ecliptic, etc.


Skeleton watch, watch whose case and various parts of the movement are made of transparent material, revealing the parts of the watch.


Mechanism designed in Germany to equalize the driving force of the mainspring armed more or less strongly.


Another term used to designate the gnomon.


Spring or silk thread... of a given length, used to suspend a pendulum.


Switch fixed on a slave pendulum which one wishes to operate in synchronism with the free pendulum of a master clock.


Speed ​​measuring instrument. In watchmaking, sports counter or chronograph equipped with a divided dial which allows speed to be read in km/h or another unit.


Operation which consists of assembling and controlling all parts of the watch.


Independent workshop or independent watchmaker reassembling all or part of the watch on behalf of a maker or manufacturer who provides it with the spare parts to assemble.


Term used to refer to bells in watches and striking clocks.


Safety device which, in a lever escapement, prevents the escape wheel from galloping.


Term used to designate chiming watches which do not have a stamp or gongs, whose hammers strike directly on the case.

Tower to copy

See "Pantograph".

Hand lathe

Ordinary lathe equipped with a crank or pedal.

Tower of hours

Dial showing the sequence of hours.

Revolver lathe

Machine which allowed the box turner to reproduce the same shapes in series from one part to another.

Tower of hours

Series of hours written on a dial.


Device designed to cancel walking deviations in vertical positions. It includes a mobile cage which carries all the exhaust components and, in its center, the regulating organ. The escapement pinion rotates around the seconds wheel, which is fixed. The cage makes one revolution/minute, it cancels by turning the deviations in vertical positions.


Rotating device invented by Breguet to improve timekeeping.

Second hand

Qualifies the seconds hand when it advances in small jumps.


In watchmaking, the bearings in which the pivots turn are called holes. Example, ruby ​​holes refer to drilled rubies.

Blind hole or dark hole

These terms refer to pivot holes that are not drilled all the way through; it is the bottom of the hole which serves as a counter-pivot.

Gait variation

Set of advances and delays of a timepiece observed in relation to a reference time standard.

Adjustment screw

Screws fixed in the serge of the first balances to modify their action.


Speed ​​governor used in striking mechanisms to control the speed of the cog.