Watch Glossary

Besides all the complications of a watch, the lingo of the industry can be a little complicated itself. Here is a glossary of terms frequently used in the watch industry.

A

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 or parts of the movements.

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.

Each ATM is equal to 10 meters.

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 winding the spring tight) by means of an appropriate mechanism. The spring ‘unwinding’ itself is what powers the watch.
 

B

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.
 

C

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. Many watches are ‘identified’ or referred to by their calibre numbers.

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. Simply, a stop watch. 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.). This means that the movement has been tested in a variety of conditions prior to being placed in the watch. COSC certification basically requires the movement to run within +/- 3 minutes a month. All Rolexes and Breitling carry this certification.

Column-Wheel-
Part of chronograph movements, governing the functions of various levers and parts of the chronograph operation, in the shape of a small-toothed steel cylinder. It is controlled by pushers through levers that hold and release it. It is a very precise and usually preferred type of chronograph operation.  Point: makes the action easier and more precise, less energy wasted.

Crystal-
The transparent cover on a watch face made of glass crystal, synthetic sapphire,  mineral 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 set the time and date or manually wind the watch.
 

D

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. Many high end companies use silver as the base for their dials.

Dial Window-
See Aperture.

Divers Watch-
A watch that is water resistant to 200M, has a one-way (unidirectional)  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 another time zone.
 

E

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. Mean time divides the earths orbit around the sun into even 24 hour days. Due to the earth’s elliptical orbit, the days actually vary in length. Summer and winter soltice are the longest and shortest days respectively. These two extremes represent  about a +16 minute to a -14 minute variation. 

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

F

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. Most ‘flyback’ hands are placed on pie shaped counters for easy identification.

 

G

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. These watches are easily distinguished by the long slender ‘slide’ on the 9 oclock side of the case.

GMT-
Greenwich Mean Time. Originally, the time zone which was based in Greenwich, England.  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.
 

H

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. Also referred to as lugs.
 

J

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.
 

L

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.
 

M

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. Manufacturers are quite rare, currently less than 10 exist.

Minute Repeater-
A timepiece that sounds hours, quarters and minutes as requested. A feature found on the Breitling Aerospace, this was originally much more useful a function before electricity and night lights.

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.  A typical moonphase is 29 ½ days. Most watches with a moon phase will only attempt to maintain the minimal accuracy of the 29 1/2 days. The actual moonphase is 29 days 12 hours and 14 plus minutes. Several brands make complicated moon phase indicators with extraordinary precision.

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. Basically, the engine which drives the watch.
 

P

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. The vast majority or watches carry a 40 hour reserve, based on a shared mainspring common to the swiss industry. Longer power reserves are often considered in the same light as a complication.
 

Q

Quartz Movement-
A movement powered by a quartz crystal that keeps very accurate time. The battery emits a pulse which is ‘regulated’ by the quartz.  Quartz watches should be in the + or – a second or two a month. Breitling makes a ‘Super-Quartz’ which regulates the accuracy twice, ensuring amazing accuracy- a second or so variance a year.

 

R

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.
 

S

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. Often distinguishable by a pusher at 10 oclock. The complication is designed to enable the wearer to measure shorter intervals or time, such as individual laps, while still measuring a larger interval, such as the entire race.  For a reputable Swiss company, expect the split second addition to a chrono to add substantially to the price. Truly a collector or watch-geek complication.

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

T

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. A single master watchmaker would require 6 months to complete a tourbillion. The least expensive tourbillion from a manufacture retails for over 40 thousand with out any other compliaction.

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.
 

U

Universal Time-
Mean solar time for the Greenwich meridian, but counted from noon to noon.

V

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. Most watches vibrate a 28,800 in our stock. Notable differences include the Zenith El Primero movement which works at 36000 vibrations per hour. Basically, a chrono can only measure intervals as small as the vibration rate will allow. For instance, the El Primero can measure in tenths of seconds, where Breitlings, vibrating at 28800 can only measure eights of a second.  The more vibrations which take place typically mean two things, a greater accuracy to the timekeeping, and since there is more movement, a greater chance or repair. Hence the double-edged sword of speeding up the movement.
 

W

Water Resistant-
Describes a watch case designed to prevent water from entering. This is a misnomer in the watch world.  30 meter water resistant means it is ok to wash your hands or splash around.  50 meter means you can jump in the pool, but not serious swimming or diving.  100 meter means a tleast the case or crown in screw-down, and you comfortably wear the watch around pools or the beach.  200 meter means that both the crown and case back are screw-down and the watch is designed to have diving capabilities.  300 meter plus are extreme pieces which almost no one will ever require.  Stream particles are smaller than water, showers and hot tubs always pose a greater risk than swimming.