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Measurement in degrees of the movement of a balance-and-spring assembly: amplitude is the angle between the position of equilibrium and its maximum elongation.


Refers to time display using hands.


Dial opening revealing the indications provided on disks rotating under the dial.


Raised numeral or hour-marker, applied to or riveted to the dial.


An activity carried out by the Grand Complications workshop. The watchmakers themselves perform certain finishing operations such as polishing steel parts or chamfering bridges.


A collection inspired by the Nautilus, created in 1996. It is distinguished by the complexity of its case shape, equipped with a screw-down crown, framing a superbly finished black textured dial. Aquanaut watches are available in two sizes (medium and large) and in two versions (gold and steel), on a « Tropical » composite strap or metal bracelet.


Usual way of showing the numerals. Arabic numerals: As opposed to Roman numerals: I, II, III...


Elongated part linking certain parts of a mechanism within a movement (such as the arm of a wheel, for example).

Art Deco

An artistic movement stemming from the Decorative Arts Exhibition in Paris in 1925, which asserts a taste for straight lines and the geometrical interpretation of nature's forms.



The lower part of the case, fixed beneath the case middle. The case, either in metal or in sapphire crystal to reveal the movement, may be of the screw-down, Snap-On, screw-on or hinged dust cover type.

· Screw-down back: the back and the case middle are respectively fitted with a screw thread and are thus screwed to each other.

· Snap-on back: the back is held on to the case middle by pressure.

· Screw-on back: the back is held on to the case middle by four screws.

· Hinged dust cover: the sapphire crystal is held on to the case middle by pressure, and the dust cover is hinged to the case middle, enabling one to open to reveal the movement.


A gemstone cut.

Balance and spring assembly

The regulating organ of a mechanical movement. The balance-and-spring assembly, composed of a balance and a balance-spring, oscillates under the impetus of the escapement.

Balance roller

Disc-shaped escapement component. The balance roller receives the impulses from the pallets via its impulse-pin.


Synonymous with a balance-bridge. The balance-cock has a special shape, from which it gets its name, which reveals the balance.


Small spring coiled into a spiral, an integral part of the balance-and-spring assembly.

Ball-bearing mechanism

Mechanical device enabling two parts to roll over each other instead of sliding.


The part of a mechanical movement that enables the accumulation of energy. The barrel is composed of a wheel and drum (cylindrical case) with a cover. It houses the mainspring which coils around the barrel arbor under the impetus of the ratchet wheel.

Barrel arbor

The stem around which the mainspring coils.

Barrel drum

The lateral wall of the barrel, fitted with a hook to receive the mainspring.

Base plate

Central plate of the movement, made in brass or nickel silver, on which the movement components are assembled. The upper side of the base plate is the side facing the case back which receives the movement parts. The underside of the base plate is the side facing the dial.


Refers to hour-markers or hands featuring the elongated shape of a baton.


A German school of architecture and applied arts, renowned for having initiated the artistic movement which holds that function determines form. The Bauhaus was founded in 1919 by Walter Gropius in Weimar.


A hydrocarbon with solvent properties.


Upper part of the case which holds the glass. It is fixed above the case middle.


A French word with Swiss roots (basically meaning "to make well") which refers to the good quality of a piece of work or an object.

Binocular magnifying glass

Optical enlargement instrument with twin eyepieces enabling one to look with both eyes at once.


The first incarnation of the dial plate before it’s worked on.


A protective varnish used to coat all parts of the case and metal bracelet after polishing.


A kind of support or rest.


Alloy of copper and zinc.


· Abraham-Louis Breguet: Swiss watchmaker established in Paris (1747-1823), whose inventions include the tourbillon escapement

· Breguet numerals: numerals designed by A.-Louis Breguet,

· Breguet hands: hollowed-tip hands designed by A.-Louis Breguet.


Movement part fixed to the base plate, in which the pivot of mobile parts turn. Generally speaking, bridges are named after the mobile parts they carry. Among the easiest to recognize is the balance-bridge also named as balance-cock.


Brilliant or full-cut diamond. Brilliant is the most widely used cut for diamonds. It comprises 57 facets, meaning 1 table surrounded with 32 facets for the crown and 24 for the culet.


Engraver's chisel.


Style of chain bracelet, made from gold threads.



Refers to a hand shaped like a cable.


A complication that provides the various indications of the conventional calendar such as the date, the week, the month and the year. Watches include:

· Simple calendars: they give the date through an aperture or by means of a hand, indicating the number of the day from 1 to 31 within the month. They must be manually adjusted at the end of 30-day months and at the end of February.

· Annual calendar: a complete calendar (day, date and month), patented in 1996, which requires a single manual adjustment each year, at the end of February.

· Perpetual calendars, which take account of monthly variations, including those of leap years, until the year 2100 (the next century year not divisible by 400).

· The secular perpetual calendar, which takes account of all the variables in our calendar, including that of century years not divisible by 400. This is the most sophisticated calendar in existence.


Originally synonymous with size or dimension. Watchmakers then began to use the term to refer to the movement. They are used either as they are or to serve as a « base » for additional developments or functions. There are thus 38 different calibers for wristwatches and 6 for pocket watches in regular production within the Manufacture.


A disk with a special profile on which a sprung lever rests.


In a movement, the pinion that controls the motion-work (the gear train that drives the hour, minute and seconds hands).


· A unit of the gold purity index for gold alloys. Pure or fine gold weighs 24 carats. Watches and jewelry are crafted from 18-carat or 750 gold, an alloy containing 18/24ths or 75% of pure gold.

· A unit of weight for precious stones. One carat corresponds to 0.2 grams.


The watch case is generally composed of three parts: the case middle, the bezel and the case back.

Case middle

The middle part of the case, placed between the bezel and the back. It houses the movement.


Ring surrounding the movement and holding it inside the case.

Celestial canopy

Complication that provides a representation of the sky, as it may be observed at night. Also known as sky chart, it enables one to follow the positions of the stars and that of the moon and to visualise the various phases.

Chain bracelet

A bracelet for which the links are produced one by one from a gold wire.


Also known as beveling or in French, anglage. Here, the sharp edge between the surface and the flank of a component is manually cut or filed away to a smooth 45° curve, followed by polishing with a mechanical buffer. A chamfer is typically used to increase resistance to wear, or for aesthetic reasons.


Hand engraving technique. Champlevé consists of hollowing out a metal plate with a flat graver, thus forming small cavities to receive the enamel.

Chenier (or knuckle)

Small tube into which one inserts a pin to form a hinge.


Watch complication enabling measurement of the duration of an event. A classic chronograph comprises a chronograph or second’s hand circling the dial and another hand adding up the minutes on a counter or totalizer. Some have additional counters. Be careful not to confuse a chronograph with a chronometer!


A watch featuring high precision certified by an official body. In Switzerland, rating certificates are granted, on a one-by-one basis, by the COSC (Swiss Official Chronometer Testing Institute). Be careful not to confuse a chronometer with a chronograph!

Circular graining

In French, called perlage due to the finished resemblance to a row of tiny pearls. Here, the main plate and attached bridges are etched with a pattern of interlaced circles or bead shapes. To create the pattern, the flat end of a piece of peg wood coated with emery paste is fitted into a rotating head and pressed meticulously down on the plate to make perfectly linear rows.

Circular satin brushing

A polishing technique used for a case, and resulting in a velvety, tunnel-like image.

Circular satin finish

To form fine circular lines on the surface of a metal movement component, using a hand lathe or fine emery paper.


Convention on International Trade in Endangered Species of wild fauna and flora. This agreement between nations is intended to ensure that international trade in specimens of wild plants and animals does not threaten the survival of the species to which they belong.


Acronym for Computerized Numerical Control.

Column wheel

Central element of the split-seconds chronograph mechanism which gives the various parts (operating-lever hook, hammer, coupling lever and brake) their appropriate positions.

Comet's tail

Refers to a flaw on exterior parts: material slightly hollowed around a tiny burr.


Relating to a sequence, a well ordered succession (as opposed to simultaneous).


Button integrated within the case middle, which is pressed using the setting stylus to adjust certain specific functions.


Swiss Official Chronometer Testing Institute


In a classic chronograph, a sub dial indicating the time elapsed in minutes. There are also counters for hours or fractions of a second.


A button (which is often fluted), operated between the thumb and forefinger that is pulled into various positions and turned, generally to set the time or adjust the date. On mechanical watches, the crown (or winding crown) also serves to wind the movement. See « Winding crown ».


Gemstone cut: an essential element in highlighting the stones. The proportions chosen determine three physical phenomena: internal reflection, diffraction or dispersion, and scintillation or fire. Professionals have established a scale for evaluating the quality of cuts.

Cutting the teeth

This operation is performed by means of a milling-cutter. This tool performs two movements: a rotating movement linked to that of the wheel and pinion to be cut, and a lengthwise movement (in the direction of the axis of the mobile part).



Also known as tampography, transfer printing or pad printing. A printing process that transfers a two-dimensional image onto any two- or three-dimensional (or otherwise difficult) object. In watchmaking, an inked silicone pad is positioned meticulously over the raw blank of a dial; the pad is lowered to imprint the words and numerals onto the dial surface, which is then allowed to dry before any further layer of transfer is added.


Refers to hands with an elongated triangular shape.


Plate with a metal base, visible through a glass, which carries certain indications such as the hours, minutes and seconds. Dials are generally in brass. The exceptions are those that are gold colored, sun burst blue, models paved with precious stones, or for some Grand Complications which are made from solid gold plates. Particular care is devoted to their finish. They may be embossed, guilloché, galvanized, painted, metallic, gem-set or genuine enamel.


Precious stone: pure crystallized carbon, generally colorless, occasionally pink, yellow or blue in color. A diamond, which is exceptionally hard, scratches all other bodies, but can only be scratched by itself Die

Steel plate representing the hollowed reproduction of a part to be cut out or stamped. The material placed on the die takes its shape by being struck with a punch.


In watchmaking, refers to display by means of numbers with no hands.


Flat, thin disk carrying the indications which are successively displayed through an aperture as the disk rotates under the dial.


In either a mechanical watch or a quartz watch, the display is shown by hands or through apertures, driven by a gear train.

Divine proportion

A mathematical ratio of homogenous size symbolizing the perfect equilibrium of shapes (1/1.6181). Also known as "the golden section", it forms the basis of the design of the Golden Ellipse.


Penetrating, passing through. For example, the drilling of pivot-holes.

Drilling for stone setting

Preparation for gem-setting by forming the holes that will accommodate the stones. This operation is a machining operation.



Chemical decomposition achieved by the action of an electric current. Certain metals are electrolyzed in order to apply them on others in fine layers.


Stamping a motif in metal with imprints embossed using a press.


Green colored gemstone, a variety of beryl. Most widely used gemstone cut for emeralds.


A finishing technique used on metal cases and bracelets to achieve a smooth and shiny surface and remove any flaws. The process involves gently rubbing the piece against an abrasive strip in a figure-of-eight pattern to give a soft luster. This is also called lapping when an oil- or water-based slurry of sanding abrasive is used.

Emery paper

Abrasive mixture coated on paper. Emery paper is used in particular for polishing, smoothing down and creating a circular satin finish.


Translucent substance that takes on various colors by adding metallic oxides. When fired in the furnace, it adheres to metal and acquires the consistency of glass. It may be applied in a single color on certain dials. Figurative painting is also used to create decorative motifs. On watches, these decorative motifs are generally created using two techniques:

· Miniature enamel painting: the reproduction of paintings in miniature, generally on the cases of pocket watches. Small touches and successive layers are applied to a white enamel base and successively fired in a furnace at 850°C. A layer of transparent enamel is then applied to perfect this work. This finish is called "flux".

· Cloisonné enamel: this technique, generally used for table clocks, consists of creating cavities marked out by gold wires, in which the enamels are applied in layers and successively fired in a furnace at 850°C.


A technique where colored glass or enamel pigments are ground to a fine powder, mixed with water or oil and painted meticulously onto a prepared metal surface. Once dry, the piece is fired in a kiln at temperatures of around 850°C, so that the powdered glass or pigment melts to form a new, impregnable surface and fuses to the metal base.

Energy distribution

· in a mechanical watch, the energy is distributed progressively by a step-by-step escapement, consisting of pallets and an escape wheel with a special profile.

· in a quartz watch, the energy is distributed by a stepping motor.

Energy production

· In a mechanical watch, this implies manual or automatic winding.

· In a quartz watch, energy is produced by a battery.

Energy transmission and division of time

Stage no. 3 in the working of any watch: in both mechanical and quartz watches, the energy is transmitted by a gear train which simultaneously divides up time. In the former case, it is powered by the mainspring; and in the latter, by a stepping motor.


A deeply creative skill where aesthetically pleasing shapes and flourishes are etched on cases and dials. The artist first creates the design with a pencil sketch, then transfers it to the metal surface with a burin for fine lines, or a graver for broader furrows, focusing on the tiny canvas through a binocular microscope.

Equation of time

Complication which indicates the difference between conventional time (mean time) and the time determined by the position of the sun (real time). This difference ranges between –16 and + 14 minutes, depending on the day of the year.


The date when the duration of the day is equal to that of the night. There are two equinoxes per year which correspond to the start of spring and that of autumn.


The organ of a mechanical movement that enables distribution of energy step by step (and not all at once). The escapement, composed of a wheel with a special shape (curved teeth) and pallets, maintains the oscillations of the regulating organ, the balance-and-spring assembly.


Banking of a lever escapement when it is cut out of the plate and is not in the form of pins (solid banking). This term is specific to Geneva watchmaking.


Set of external parts of a watch: case, dial, hands, glass, crown, strap/bracelet, etc. (to the exclusion of movement components).



Having facets, such as on gemstones.


Angling the planes of some raised three-dimensional numerals, which will sit on a dial. A machine fitted with sharp diamond tools is used to incise the batons or hour markers to make visibility even more acute.

Fancy diamond

Colored diamond.

Fine working

Part of the case hand-finishing. This stage includes trimming or filing off of residue material, and it’s here that attachments are soldered, hinges are made for cases with dust covers and their openings adjusted, and preparations are made for polishing.


Refers to the work of a company that buys watch components from outside and only handles assembly, adjustment, fitting the hands and casing up. One must distinguish between a finishing workshops as opposed to a Manufacture.


Fitters assemble the movement components and the parts that make up the case and bracelet, combining the cases, bezels, backs, sapphire crystals, joints, and winding crowns. Operations are carried out in conditions of absolute cleanliness. At this stage, grueling tests are carried out on each watch, for everything from water resistance to design finesse.

Fold-over clasp

A clasp that opens by folding over, without being detached from the two parts of the bracelet.


Tip of the pallets which alternately pushes the impulse-pin placed under the balance and spring assembly so as to maintain its oscillations.


Number of oscillations per second. Frequency is expressed in Hertz (Hz). 1 hertz = 1 oscillation = 2 vibrations per second.

· the frequency of the balance and spring assembly of mechanical watches is no higher than 5 Hertz (5 oscillations/sec.).

· The frequency of quartz is 32,000 Hertz (32,000 oscillations/second).




Also known as electroplating, this is the process of applying a protective coating over a metal to prevent rusting, which helps keep the material free from impediment (damp or sea air can all create corrosion over time) and in perfect working order for much longer. During galvanization, one metal is electrochemically covered with another – for example, bridges and plates are protected by a fine layer of rhodium. Electroplating can also be used to change a dial’s color.

Galvanized/Galvanic plating

Technique for plating metal by electrolysis. For example, the bridges and plates are protected from oxidation by a fine layer of rhodium.


Gear train composed of wheels and toothed pinions.


Set of wheels driven in an interdependent movement. The gear-train generally called the going train is the one that transmits energy and divides up time. It comprises the hour wheel, the minute wheel and the second’s wheel. Variable sets of wheels result in reduction and in different speeds of rotation:

· Intermediate wheel gear train: maintains the speed of rotation

· Multiplying gear train: the movement accelerates from one wheel to the next.

· Reduction gear train: the rotation slows down from one wheel to the next.


Specialist of fine stones and precious stones, scientifically called "gems".


Craftsman who sets fine stones or precious stones.


Precious stones – diamonds, rubies, sapphires or emeralds – are set manually. They are never adhesively bonded, but positioned ultra-securely by folding over the metal collars that surround them. Stones must be fastidiously placed (level, pointing in the same direction and all at the same height) to bring out their full shimmer and radiance.

Geneva stripes

Also known as Côtes de Genève. Decorative broad, straight stripes ground onto parts of watch movements such as plates, bridges or rotors.. This removes a tiny quantity of material from the surface and creates a very slightly three-dimensional wave pattern.

Geneva stripes / "Côtes de Genève"

Famous wavelike decorative pattern created on the bridges and oscillating weights of some watches. The tool required is crafted from boxwood by the craftsman himself, coated in abrasive paste and then pressed manually in order to remove an extremely small amount of material.


Thin transparent plate through which one reads off the time, and which protects the dial. A glass may also be fitted on the case back to reveal the movement. The glasses used for many watches are always in scratch-resistant sapphire and may thus also be referred to as sapphire crystals.

Golden Ellipse

Collection characterized by an elliptical case, inspired by the golden section. This "divine proportion" is not a measurement, but a mathematical ratio of homogenous size corresponding to 1/1.6181 and symbolizing the perfect equilibrium of shapes. Golden Ellipse watches were created in 1968 for men, and ladies' versions were subsequently introduced.


Coating with a thin film of gold.


Striking mechanism part:

· Generally speaking, gongs are circular steel coils, fixed at one end and which progressively surround the minute repeater movement. When struck by hammers, they vibrate and produce sounds.

· Those that wrap almost twice around the mechanism are called "Cathedral" gongs. This enhances both the quality and duration of their sound.


A pointed tool for engraving.


A disc used for polishing, coated with an abrasive substance.


A system of adjusting the balance and spring assembly, patented by Patek Philippe in 1949 and 1951. The Gyromax balance and spring assembly, which equips the company's mechanical movements, replaces the traditional index-assembly or regulator-assembly system. The adjustment depends on the direction of the asymmetrical inertia-blocks placed on the balance-ring, enabling one to modify a watch which is gaining or losing time.



Refers to a hand that looks somewhat like a hair.


A component in striking watches: Hammers are small levers with a weight at one end which strike gongs to produce sounds.


Metal part which points to various indications on the dial, it may take a variety of shapes and forms, including dauphine, Breguet, leaf, baton, hair, pear, cabled or Louis XV.


Refers to the steel parts used in movements: See "Hardening".


Modification of the molecular structure of the steel part in order to make it harder or more flexible. Firing it in the furnace at a temperature of 800°C and then cooling it down quickly in oil at around 40°C make the metal harder, but also more brittle. To stabilize the material, it is reheated to various temperatures and for various lengths of time, depending on the flexibility required for the function the part is to serve.


Gemstone cut.

Heart (system)

Steel part enabling the return in one or the other direction of the chronograph hand and/or the split seconds chronograph hand.


Unit of frequency of a movement.

Hobnail pattern

Motif forming small pyramid shapes which is among the most famous types of guilloché work, engraved ornamentation composed of regularly interwoven hollowed lines.

Hour marker

Symbolic character serving to indicate the subdivisions of time, on the dial. The hour markers, whether pointed baton or rounded baton, may be flat (painted) or raised (appliques). They are to be distinguished from numerals, which are characters representing numbers.

Hunter pocket watch

Pocket watch with a cover, which is distinguished by a winding stem at 3 o'clock and a seconds hand placed along the 12 o'clock – 6 o'clock axis.



Cylindrical, elongated escapement part, generally made from ruby. The impulse pin receives the impulses given by the pallet-fork. It is fixed to the roller, under the balance-spring for which it serves to maintain the oscillations.


Traditional system for adjusting the balance and spring assembly. In some movements, it is replaced by an exclusive system named Gyromax.


Small asymmetrical metal part which acts by inertia. The Gyromax balance and spring assembly, is poised thanks to adjustable inertia-blocks. This equilibrium governs the regularity of rate of the movement, with a minimum gain or loss.

Inertial flywheel

Regulates the speed of rotation in striking watches.

Integrated circuit

Component of quartz movements which powers the electrical organs, transmits energy to the stepping motor and divides up the frequency of the quartz.


Abbreviation for power reserve indicator, a complication which displays the time left during which a mechanical movement can continue to run without winding.



In a movement, a synthetic ruby that serves to reduce friction on the staffs of the pivots. Jewels belong to the "other parts" category.


Steel part that locks certain wheels, known as star wheels, by resting against their teeth. Also known as a jumper spring.

Jumping hour

Hour appearing in an aperture thanks to a rotating disk, and which replaces an Hours hand. It is referred to as "jumping" since, every hour on the hour, it changes by jumping abruptly from one numeral to the next.



Machine tool used to fashion parts by causing them to rotate. Lathes may be operated by hand or automatically.


Term used in watchmaking to refer to a hand shaped like a leaf.

Leap year

In our calendar, a year when the month of February has 29 days instead of 28. Generally speaking, leap years occur every 4 years. Century years, which are multiples of 100, are an exception: only those divisible by 400 are leap years.


Pivoting part subject to the action of a spring.


A steel or brass part within a mechanical watch shaped like a ship's anchor. It makes up the escapement together with a special-shaped wheel with curved teeth, called the lever wheel.


A hand engraving technique. Fine line engraving, made with a burin.

Louis XV

Refers to a hand with Louis XV style motif.

Lugs (horns)

Parts extending from the case middle between which a spring bar holds the strap or bracelet.



Synonymous with cutting out. Working or fashioning raw material. Forming holes and recesses, milling, turning, drilling and threading are all machining operations. The watch parts are machined on computerized numerical control machines.


Motor spring of a mechanical movement. As it coils inside the barrel, it accumulates energy. As it uncoils, it transmits the energy to the hands via a gear-train. The mainspring is fitted with a slipping spring when the movement is self-winding.

Manually wound

A manually wound movement is a mechanical movement that is wound by hand (using the winding crown).


Refers to a company that makes a watch in its entirety: conception, development, production, assembly and adjustment. One speaks of a Manufacture as opposed to a finishing workshop.


Elongated gemstone cut, synonymous with navette cut.

Mechanically made bracelet

A bracelet with metal links produced on CNC machinery.


Combination of parts which, together, operate a function. A watch movement comprises several mechanisms.


Refers to a flawed appearance on watch exterior parts: a tiny, almost invisible scratch.


A cutting process that removes material from the very surface of a piece, smoothing and refining tiny recesses and shaping holes for gems and hour markers. Performed with a high-speed milling lathe, this is exacting and complex work.

Minute repeater

Minute repeaters: A complication which strikes or chimes (on request by operating a slide piece, or automatically).  they strike the hours, quarters and minutes, exclusively on request.

Minute track

The minute track is the mode of displaying the minutes (railway track).


Describes the particularly soft and luminous result of polishing. Mirror polish is also called black or specular polish.

Mirror polishing

Also known as poli miroir or poli noir. Regarded as the most demanding of all polishing techniques, true mirror polishing is always done by hand and is found only in the most exceptional timepieces. It’s achieved by rubbing the watch part on a flat zinc plate coated with a paste of very fine diamond dust in oil. The result is a finish that, catching the light from one angle, shines like a silver mirror and, catching it from the other, is a plush matt black.

Moon phases

A complication which depicts the evolution of the moon, as seen from the earth. The indication is generally shown in an aperture, but may sometimes be displayed by a hand.


In a movement, the motion-work is the gear train which drives the hour, minute and seconds hands.


There are three types of movements, or calibers, which watches:

· Mechanical manually wound movements

· Mechanical self-winding movements.

· Quartz movements

Movement regulation

· In a mechanical watch, the regularity of the running of the movement is ensured by the oscillations of the balance and spring assembly.

· In a quartz watch, the regularity of the running of the movement is ensured by the oscillations of the quartz.



Elongated gemstone cut, synonymous with the marquise cut.

Nickel silver

Copper, zinc and nickel alloy, oxidises less easily than brass.

NIHS 92-10 (Norm)

Water resistance norm equivalent to the international ISO-2291 norm. (1 bar = 10 meters).


Character representing a number used to indicate the units of time on the dial. The Arabic, Roman or Breguet style numerals may be flat (painted) or raised (appliques). They are different from symbolic characters such as hour markers.



Fine gemstone, a variety of agate featuring regular concentric zones of various colors. The crowns of Twenty~4® steel watches are set with an onyx.


A solid white finish with a silky rendering. It is achieved by spraying a silvery coating of powder before applying a transparent layer.

Oscillating weight



In a mechanical watch, the movement of the balance and spring assembly in both directions, to and fro. In a quartz watch, the double vibration of the quartz. One oscillation comprises two vibrations.

Other parts

Refers to a certain number of movement parts, apart from the plates, bridges, wheel trains and steel parts, as "other parts".


Gemstone cut.



Extremely hard white metal.


· Hand shape

· Gemstone cut, shaped like the fruit with the same name.


A property of certain crystals such as quartz. The piezo-electricity of quartz means that it is deformed and vibrates under the effect of a low-intensity electric current. Its vibrations are remarkably constant.

Pin (on a buckle)

A pointed metal prong which goes through various holes in the leather, on traditional straps.

Pin (on a movement)

Small cylindrical pegs driven in, used for fixing, guiding or stopping.

Pin buckle

Fastens the strap. A metal buckle composed of a ring or rectangle and a prong called a pin.


A toothed movement part which, combined with a wheel top, forms a wheel.


Hollow metal cylindrical part used for many purposes (pivoting, supporting arbors, protecting parts, etc.) Pipes belong to the category of "other parts".


Movement component which rotates in a fixed support.

Pivot shank

Small stem or rod.


Method of depositing or transferring metal on the dial, for a specific surface rendering.


Precious metal. 950 platinum (95% pure platinum and 5% other metals) is used for making watches. It is the hardest material of all to work and tools often break in the process. It takes three to four times longer than working gold.

Pocket watch

Watch intended to be carried in the pocket of a waistcoat which are exclusively mechanical.


May refer to a flaw on watch exterior parts: a small burr.


Also known as riveting. Here, hour markers are definitively fixed into the fabric of the watch dial using a diamond grinding wheel or a pointe – a “spotting drill.” The wheel or drill flattens the numerals’ feet once they’ve been slotted through tiny pilot holes in the dial, thus securing them firmly.


Tool or machine used to polish or to create certain decorative motifs such as circular-graining.


One of the most important finishing operations, polishing brings each aspect of a watch into sharp relief, highlighting everything from gemsetting and enameling to the engraving. Polishing at Patek Philippe is done by hand, as it always has been, using a “free floating” method, which means without pressure. A tricky technique, it takes experience, a deft touch and speedy reflexes to master. The craftsmen use a series of different sized disks of fabric, felt, or natural or synthetic hair, depending on the effect they need to achieve. Polishing is also perfect to correct almost imperceptible flaws.

Polishing the faces of the pinion leaves

Cleaning the flat inner planes of the pinion’s teeth (the “leaves”). Since the surface is so compact, the pinion is fitted into a wheel top, with a support plate to prevent any damage. Polishing is done with a hard metal grinding wheel coated with abrasive paste. The result is a gleaming sheen, and surfaces with extra protection against oxidation.

Polishing the pinion ends

Pinions are the tiny cogwheels fundamental to the movement of a watch, composed of an axle and wings – elongated gear teeth known as “leaves.” The pivots, or ends, of the pinion are extremely small, but can be worked on if the pinion is fitted into a supporting wheel plate so that the pivots protrude. A leather grinding wheel is used until the ends are smooth and convex.

Polishing the pinion teeth

The minuscule pivot is put on a support, and a wooden grinding wheel painted with abrasive is lowered into its teeth, driving the pinion and polishing the teeth to a silvery gloss. This reduces friction on the steel gears, and gives a longer life to the gear-train.

Power reserve

A complication that indicates the state of the power reserve: the time during which a mechanical movement can continue running without being wound, ranging from 48 hours to 10 days for Patek Philippe watches.

Pre-assembly, Pre-assemble

Pre-assembling bridges means driving the jewels into the sunk holes.

Press (mechanism)

· A mechanism or device that exercises pressure on a solid object.


· Synonymous with cutting out with a "cutter". Striking the material with a punch on a die to cut out a shape.

· In making watch exteriors, pressing means not only cutting out but also shaping, correcting or finishing. After cutting out the rough shape of the part, the metal is distorted by pressing successively to obtain the desired shape.


Gemstone cut, with a square base.


Cutting parts, particularly pinions, from rotating cylindrical metal bars, using dedicated tools.

Protective coating

Red varnish placed in the hollows of gilded numbers and logos in order to protect them from subsequent surface treatments.


Sharp-edged tool which stamps the material placed on a die, during the cutting out or pressing process.

Push-button (push-piece)

A button pressed with the finger to activate certain functions, such as those of a chronograph.



· In its natural state, quartz is a rock crystal.

· For watch movements, the quartz is manufactured synthetically. It is used for its piezo-electric properties.


Abbreviation for "Minute repeater", in the Patek Philippe typology.


Steel part with straight toothing used in triggering the minute-repeater mechanism.

Railway track minute circle

Peripheral indication of the minutes on the dial reminiscent of the rails on a railway track.

Ratchet wheel

A toothed wheel fixed by a square hole to the barrel arbor. It is placed between the crown wheel and the barrel arbor.


Hollow cut in bridges and plates to receive various components.


Hand engraving technique, also called pounced ornament. Relief is a "trompe l'oeil" or optical illusion type of modelling in the manner of bas-relief, created using a graver.

Repassage, Repasser

Activity of the Grand Complications workshop. The watchmaker assembles, adjusts, files and balances movement parts. He adapts the parts to each other so that they run perfectly.

Restoration or repair, rhabillage

Repairing, restoring a watch to good working order. Refers to service or repair departments (ICS).

Retrograde hand

A hand with a tip moving over the arc of a circle instead of a circle. When it reaches the end of its path, it returns instantly to its point of departure. Retrograde hands may give various indications such as hours and minutes.


Metal often used to give a beautiful silvery color to white gold (for watch exteriors) or for certain movement parts, especially bridges and plates. On the brass or the nickel silver of the latter, it also serves to protect against oxidization.

Rhodium plating

Coating with a fine layer of rhodium by electrolysis.


Term used to describe D-color (exceptional white +) or E-color (exceptional white) diamonds.


System writing figures as letters: Roman numerals: I (1). V (5). X (10. L (50). C (100. D (500). M (1000).


Component of self-winding movements, synonymous with oscillating weight. The rotor is a heavy part which rotates or oscillates thanks to wrist movements and automatically winds the mainspring. Nonetheless, when the watch is not worn for a certain period of time, one resorts to manual winding to reactivate the accumulation of energy in the barrel. When they are particularly small in size, they are called mini-rotors.

Rounding off

On a rounding-off cutter, the watchmaker operates a milling-cutter to correct the teeth and the diameter. This operation is performed exclusively when restoring antique watches, or when the watchmaker is working on the basis of a movement blank.


Referred to in French as "bassiné", in reference to "bassine" type cases with rounded profile that are smooth all around. For example, certain hour markers are referred to as round-polished markers.

Running equation

Complication that consists of indicating solar time (real time) thanks to a second Minutes hand.



· Transparent synthetic material for watch glasses (or crystals) which has the property of being scratch-resistant.

· Gemstone, a variety of corundum. It is generally blue, but may be pink, yellow, etc.

Satin brushing

A polishing technique where the surface of the metal is “drawn out” or smoothed with a tool coated in fine emery paste to achieve a matt appearance and a finely striated effect.


Describes a shiny surface toned down by a slightly frosted effect.


Refers to a flaw on watch exterior parts: small line, shallow furrow.


A self-winding movement is a mechanical movement that is wound by wrist movements thanks to the oscillating weight (or rotor).


Device facilitating the mobility of jewels so as to absorb shocks.

Sidereal time

A complication that displays sidereal time. It is based on the earth's rotation in relation to a fixed point, such as a star. It is invariable for a given point and shorter than the average time of 3 min. 56 sec. per day (23 hours, 56 minutes, 4 seconds /24 hours).


Sinking a recess or concave chamfer (slightly hollowed cut edge).

Sinking the holes

A concave chamfer or incurving edge – called a sink – is carved into a previously machined hole and highly polished. The chamfer not only enables easier positioning of screws, but also ensures that a jewel driven into a hole will shine with even more radiance.

Sinking the wheels

In the past when oils were less stable, the sinking of wheels kept the oil more directed toward the axis. Today, it’s a solely aesthetic job. The different wheels all receive a polished sink – a concave chamfer or slightly hollowed groove – made using a diamond cutting tool on a mechanical lathe, which is lowered onto the tiny, impeccably placed piece.


Refers to a movement that is open worked and engraved by hand.

Slide piece

On a striking or minute repeater watch, the part that slides along the case middle to activate the striking mechanism or switches it to silent mode.

Slipping spring

A potential characteristic of the mainspring. When the watch is worn, it is automatically wound constantly and when coiled to the maximum, excess tension might break the mainspring. The outermost tip of the spring is thus not entirely fixed. It is equipped with a slipping spring, a blade that slides intermittently against the inside wall of the drum equipped with three notches if the tension becomes excessive.

Small second’s hand

Seconds indicated on a small sub dial, and not in the center.

Smoothing down

Usually used on a movement component. With the tiny steel part sitting on a cork work base, all lines and scratches are blended away (or “drawn out”), most often with emery paper.


Date of the longest day and the shortest day of the year. There are two solstices per year, corresponding to the start of the summer and to that of the winter.

Split seconds chronograph

An additional complication within a chronograph. A split seconds chronograph features an additional second’s hand that is superimposed on the chronograph hand. It enables measurement of a lap or split time, without stopping the measurement in progress. This process can be repeated several times in a row. After displaying the split time, the additional seconds hand catches up with the chronograph hand.


A steel blade that pulls a lever to its point of departure.

Spring bar

A thin metal rod fixed between the horns/lugs (or attachments) of the case by means of two small holes on the side, for attaching the leather strap or metal bracelet.

Star wheel

Type of wheel with large triangular teeth, periodically locked by a jumper-spring. Its shape resembles that of a star.


· the term "steel parts" encompasses all steel parts of the movement. This is always hardened steel.

· Stainless steel: steel used for watch exteriors. It is a material that is hard to work with, particularly to set with gems.


Metal cylindrical movement part.

· Winding stem: it ensures the winding of a mechanical manually wound movement. Operated by the crown, it successively drives the winding pinion placed at its end, then the crown wheel, and finally the escape wheel.

· Split stem: winding stem for watches with a monopoly case. The movement is inserted into the case with a short part of the winding stem ("plug" part). The second part of the stem ("socket" part) is thus inserted through the side of the case thanks to the tube.

Stepping motor

Battery-driven motor which distributes the energy in a quartz movement. It plays the same role as the escapement in a mechanical movement.

Straight graining

With a tool like an abrasive pencil, the craftsman rubs parallel strokes along the squared-off sides of a part, leaving the metal with a velvety matt slab.


Strip/band of leather (or other non-metal material) that holds the watch to the wrist.


Small cylinder driven or screwed in, serving as a support for a part to turn freely.


A dial finish obtained by brushing the surface with an abrasive paste to create rays spreading from the center to the rim.



Cutting a screw-thread on a rod or in a hole.

Time zones

Simultaneous indication of the time in several time zones. The most common models are dual time zone watches which give home time and local time in the place one is traveling to.


Measuring elapsed time by means of a chronograph.



A device invented in 1801 by A.-L. Breguet, eliminates variations in rate due to gravity, in vertical positions. The tourbillon comprises a mobile carriage carrying the escapement and balance and spring assembly components.


The removal of any minute burrs or tiny scraps of material left on the dial plate or bridge by machining, usually using a scraper with a narrow spear-like head.


Fashioning with a lathe, whether hand-operated or engine-driven.


Fine pincers used to pick up small objects (always used in plural form).



Disequilibrium of a rotating part.


Variation in rate

When referring to watches, means the gain or loss each day. This is particularly noticeable in a mechanical watch, and virtually nil in a quartz watch. It must fall within strict tolerance thresholds in order for the movement to be granted chronometer certification.

Velvet finishing

A decoration, usually used on dials, achieved with two consecutive styles of sand-blasting, first by bombarding the metal with a mix of powdered rock and water until the surface has a fine, matt nap, then using cream of tartar as an abrasive, which imparts a cream-colored, velour look.

Vertical satin brushing

A dial decoration technique using a small brush with firm copper bristles and an abrasive paste. The brush is then drawn carefully downward.


In a mechanical watch, the movement of the balance and spring assembly in one direction, forwards and backwards. In a quartz watch, the simple vibration of the quartz. A vibration is equivalent to a half-oscillation.



Case fitted with a watch movement which shows the time and various additional indications with varying degrees of complexity.


Circular movement part (wheel top + pinion) that spins around an axis and transmits force or energy.

Wheel plate

Movement part which, together with a pinion, forms a wheel.


Winding the spring of a mechanical watch. This winding may be done manually or automatically by wrist movements.

Winding mechanism

Part of a mechanical watch, designed for winding:

· The winding mechanism of manually wound movements is operated by the crown. The system was developed by Jean-Adrien Philippe in 1842 to replace the key, placed on the back of watch cases.

· The winding mechanism of self-winding watches is driven by the rotor thanks to wrist movements.


Watch intended to be worn on the wrist. There are mechanical and quartz wristwatches.