With so many specialized terms used to describe the features of watches, it's our duty to offer some explanations and definitions on the most commonly used watch terminology. We'll be happy to assist you with more information on the various watch terms contact us

Annual calendar
A watch displaying the day, date, month, and 24 hours that adjusts automatically for short and long months. An annual calendar requires only a single manual correction per year from the end of February to the 1st of March.

Aperture (or dial window)
A small opening in a dial plate through which various information is displayed: date, hours, day of the week.

Applique
Numerals or symbols stuck or riveted to a dial.

Assembling and finishing
The process of assembling and testing all parts of a watch.

ATM
Unit of pressure used in watch making to indicate the level of water resistance.

Automatic Watch
An automatic watch contains a self-winding, mechanical watch movement that is wound by the movement of the wearer. A heavy pivoted rotor turning back and forth transmits its energy to the spring by means of an appropriate mechanism.

Balance
A wheel-like device which, by rotating back and forth, regulates the gear train movement as uniform as possible.

Balance-cock
A separate bridge holding the balance and regulator assemblies.

Barrel
Thick wheel featuring a toothed disc on one face and containing the mainspring of a watch movement.

Bezel
A retaining ring that holds the watch crystal over the dial, snap-fitted or otherwise secured to the case.

Bolt, or slide
An operating part, on repeater watches, made of the same metal as the case and shifted along the caseband with the fingernail. The repeating-slide winds the spring of the striking mechanism.

Bottom plate
A metal plate bearing the bridges and various parts of the movement.

Bridge (or bar, or cock)
A metal movement part that is attached to a bottom plate and holds at least one bearing of a rotating part.

Calibre
In simple terms, it means "diameter". In watchmaking, the term refers to the specific layout and shape of a movement and the bridges, and its various components as well as the designer of the movement.

Carillon
Striking mechanism, or chime, that involves two or more bells of varying tones.

Central piece
Central part of the watch-case, which houses the movement.

Case
The container housing the movement of the watch and protecting it against dust, moisture, jarring and other hazards. Usually consisting of the caseband, the bezel, and the caseback.

Caseback
The bottom of the watchcase that can be opened for access to the watch movement.

Caseband
The watchcase edge between the bezel and caseback. Also called the middle.

Chamfer (or bevel)
To take down a sharp angle into a flat edge which often produces a luminous strip along the contours of the chamfered part or area. Hand chamfering results in particularly clean recessed and protruding angles.

Chronograph
Is a device that measures elapsed time. With a second hand independent of the watch's timekeeping, it rotates one revolution a minute, and can be started, stopped, and returned to zero by buttons on the caseband. Totalizers can be used to display total elapsed time from minutes into hours, and even days.

Chronometer
Technically speaking, all watches are chronometers. Today, watches must qualify as chronometers, and most all chronometers today meet the ISO 3159 standard set by the Swiss Official Chronometer Control (C.O.S.C.).

Crystal
The transparent cover on a watch face made of glass crystal, synthetic sapphire or plastic. Better watches often have a sapphire crystal which is highly resistant to scratching or shattering.

Circular Graining
A surface decoration of slightly overlapping concentric circles, often found on the bridges and base of watch movements and even occasionally on dials.

Clasp
The attachment used to connect the two ends of the watch strap or bracelet around the wrist.

Complications
Supplementary time mechanisms, with the exception of the display of hours, minutes and seconds, that are added to a basic movement. Complications belong to three main categories: those that provide extra time indications; those that strike or chime the time of day; and those that provide a variety of astronomical indications. "Grand Complication" watches feature mechanisms from all three above categories.

"Côtes de Genève"
The term means "Geneva ribbing" which are regular, parallel strokes that impart a ribbed aspect to the surface of given parts, often the bars and bridges of a movement.

Crown
Knurled or grooved knob located on the outside of a watch case and used to manually wind the watch.

Dial
Disc or plate made of metal or another substance, inscribed with various markings, including obvious indications for the hours, minutes and seconds. Uniquely varied in shape, decoration and material, they are inscribed with numerals, figures, symbols, divisions and other information.

Dial Window
See Aperture.

Divers Watch
A watch that is water resistant to 200M, has a one-way rotating bezel and a screw-on crown and back, has a metal bracelet or rubber strap.

Dual Time Zone
A watch that displays two time zones, to simultaneously keep track of local time and time in another country.

Ebauche
A French term for a movement blank, which is an incomplete watch movement before its assembly is completed, and comprises the main plate, the bridges, the train, the winding and setting mechanism and the regulator. Not part of the ebauche is the timing system, the escapement and the mainspring.

Etablissage
French term for the method of manufacturing watches and/or movements by assembling their various components. It generally includes the following operations: receipt, inspection and stocking of the "ébauche", the regulating elements and the other parts of the movement and of the make-up; assembling; springing and timing; fitting the dial and hands; casing; final inspection before packing and dispatching.

Etablisseur
French term for a watch factory which is engaged only in assembling watches, without itself producing the components, which it buys from specialist suppliers.

Equation of time
The amount of time used to compensate for difference between true solar time to the mean, or civil, solar time at any given time.

Escapement
The mechanism that "releases" the energy that maintains the oscillations of the balance wheel.

Factory, works
In the Swiss watch industry, the term "manufacture" means a factory in which watches are manufactured almost completely, as distinct from an "atelier de terminage", which is concerned only with assembling, timing, fitting the hands and casing.

Fold over clasp
Hinged and jointed element, normally of the same material as the one used for the case. It allows easy fastening of the bracelet on the wrist.

Fly-back Hand, (retrograde date hand)
Usually, a hand indicating a date or time against a scale and then "flies back" to catch up with to another date or time. For example, a hand that "flies back" to the beginning of the month after reaching the 28th, 29th, 30th, or 31st day of the month.

Grand strike
("Grande sonnerie" in french)Mechanism that can automatically sound the hours and quarter hours and which repeat hours, quarters and minutes on demand.

GMT
Greenwich Mean Time. As a feature of watches, it means that two or more time zones are displayed.

Guilloche
Decoration of dials, rotors or case parts consisting of patterns made by hand or engine-turned. By the thin pattern of the resulting engravings & consisting of crossing or interlaced lines.

Hand
Indicator for the analog visualization of hours, minutes, and seconds as well as other functions.

Horology
The science of measuring time and technology of constructing instruments for its measurement or recording.

Horns
The parts on a wristwatch case, usually joined to the central piece, to which the straps are attached.

Jewel
In watchmaking, a synthetic ruby used for making low friction bearing in which the delicate pivots of the movement wheels run in. In some deluxe watches, sometimes sapphires or garnets are used.Expensive watch movements are jeweled from the barrel to the balance, and all automatic work, date and complication movements are expected to be jeweled.

Jumping hours
On a watch dial, the digital numbers representing hours appearing through a small aperture or window.

Lesser strike
("Petite sonnerie" in french)Striking-mechanism setting limited to the automatic strike of hours

Lever
Any pivoting element and anchor-shaped part made of steel or brass that is part of the escapement.

Lug
Double extension of the case middle by which a strap or bracelet is attached.

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

Manufacture
In the Swiss watch industry, this French term names companies where the watch manufacturer produces in-house all the major parts and components of a watch. Opposite from a "manufactory" which is to an "assembler" who merely puts together movements from parts acquired elsewhere, times and adjusts the movements, and fits on the hands and cases them up.

Minute repeater
A timepiece that sounds hours, quarters and minutes as requested.

Mirror polish
Extremely meticulous and elaborate polishing operation resulting in a flawlessly bright and smooth surface, absolutely free from scratches and blemishes.

Moon-phase calendar
On some watches, the display of the evolution of the lunar cycle: rising, full or waning moon.

Movement
The assembly making up the principal elements and mechanisms of a watch or clock: the winding and setting mechanism, the mainspring, the train, the escapement, and the regulating elements.

Pallet
Steel or brass part of watch that controls the small rotation of a ratchet wheel.

Perpetual calendar
A complication displaying the day of the week, the date, the month - also correcting for leap years - and the phases of the moon. Operating on the 400 year cycle, perpetual calendars require no manual correction before February 2100.Perpetual calendars are almost always self winding and, if worn constantly, are one of the most useful of all complications.

Power reserve
The time a watch will continue running based on the movement's residual winding of its mainspring.

Quartz movement
A movement powered by a quartz crystal that keeps very accurate time.

Racks
The striking mechanism incorporates three round-shaped parts called racks: one for the hours, one for the quarters and one for the minutes.

Repeater
A watch mechanism that sounds hours, quarters or minutes or repeats them on request. First designed to help the wearer to tell the time in the dark, they were always the most complex of watches and were the most difficult to miniaturize to fit into a wristwatch.

Rotor
In automatic winding mechanisms, an unbalanced, semicircular metal turns freely in both directions winding the mainspring.

Sapphire Crystal
Scratch-resistant man-made material (synthetic corundum) used for watch crystals, fitted over the dial and sometimes set into the case back.

Skeleton
Watch in which the case and various parts of the movement are cut away to reveal the watch's mechanical elements.

Slide(-bolt)
Found on the case middle and operated with a fingernail, the slide triggers or locks a function or mechanism. The repeater slide also serves to wind the striking mechanism.

Snail
Notched cam for the hours, quarters or minutes. Named after its shape, it is used to mechanically set a wide range of indications.

Split-seconds chronograph
A chronograph mechanism controlling two second hands, one called the split-seconds hand, superimposed on one another.

Stamp, swage
A precision tool that has stamps and presses components of a movement, through shaping, bending, blanking and cutting them.

Tourbillon
A regulating device that cancels the effects of gravitation on the precision of a watch movement by rotating the balance, lever and escapement around a single axis. The mechanism that even in its most conventional version, is extremely hard to manufacture.

Tonneau Watch
Describing the shape of a watch case that looks like a barrel with tow bulging sides.

Train
A set of wheels and pinions in a watch movement.

Vibration
Describes the movement of a pendulum or other oscillating element, limited by two consecutive extreme positions. The balance of a mechanical watch making five or six vibrations per second vibrates at 18,000 or 21,600 times per hour.

Water Resistant
Describes a watch case designed to prevent water from entering.