Glossary

Curious about what some of the more complex watch terminology actually means? Look no further as we explain the ins and outs of watches.

A

Alarm

Did I mislead you when I said complicated terminology… a watch featuring an alarm function that will sound or vibrate at a pre-set time.

Analogue

A watch that displays the time via a dial with hands, as opposed to a digital display.

Annual Calendar
A calendar function that automatically takes into account months with less than 31 days (not leap years). Requires adjustment once a year.

Anti-Magnetic

A watch protected against becoming magnetised (a magnetised watch may no longer be accurate as it affects the function of the mechanism).

Aperture

A small opening in the dial, often used to display month/day/date functions and other complications such as a Moon Phase.

Arbor

Refers to any post or axle in the mechanism that a moving part swings or rotates upon.

Art Deco

An eclectic design style evolved within Paris during the 1920’s, currently showing a resurgence in current dress watch trends.

Assembly

Simply, putting the component parts of a watch together. Historically, this was done entirely by hand but is now mostly automated. Watches are still inspected for quality and accuracy by hand.

Atm

Not a cash machine but a unit of measurement to indicate water resistance, specifically pressure which is measured in bar. 1 bar equates to 10 metres in depth, 10atm = 10 bar or the equivalent of 100 metres in depth. Sounds complicated? Well most watch brands now simply state a depth in metres, phew.

Automatic

Also called a self-winding watch; a watch that is wound by the movement of the wearer which in turn (via a weighted mechanism) winds the mainspring, providing energy to run the watch. A fully wound mainspring can typically store enough energy to run the watch for two days, accounting for stationary periods when the watch is on your dressing table.

Automaton

A mechanically animated figure or scene depicted on a watch dial.

Auxiliary Dial

Any smaller dial within the main dial for example part of a Chronograph.

B

Balance

A circular part which is swung back and forth by the balance spring to divide time into equal segments (like a pendulum). Each movement to and fro is called an oscillation. The balance and spring comprise the regulating organs of a mechanical watch, responsible for counting time. In an electronic / quartz watch this function is provided by a quartz crystal.

Balance Cock

A bar which secures the balance within the movement.

Balance Spring

Otherwise known as hairspring. A super fine spiral spring which swings the balance back and forth. Fixed to the balance and the balance cock, the length of the spring determines the duration of each oscillation. The length of the spring can be adjusted to regulate the watch.

Balance Staff

Commonly known as the ‘heart’ of a watch, this is the shaft or Arbor upon which the balance swings back and forth.

Barrel

A cylindrical box (barrel) with a toothed rim (wheel). The barrel contains the mainspring which turns on its arbor. The barrel wheel drives the Gear Train

Basic Function

The indication of hours, minutes and seconds.

Bezel

The ring around the watch face that secures the sapphire crystal. In women’s watches this is often embellished with stones for a decorative effect. A rotating bezel allows the wearer to record a specific duration. Diving watches feature a uni-directional bezel to ensure that a diver always has enough time to surface should the bezel be knocked.

Big Date

A date function with large numerals displayed through oversized apertures in the dial.

Bottom Plate

The plate onto which the movement is built. The watch dial is usually fixed to the underside of the plate.

Bridge

A metal plate used to support rotating watch gears. Also known as a bar, a bridge is a bar with two supports. Bridges are generally named after the parts they support eg Barrel Bridge.

C

Cabochon

A polished stone cut into a dome and used to decorate a watch dial or sometimes the crown.

Calendar

A function that shows the date and often the day of the week.

Calibre

A term used to identify the type of movement eg ETA 251.471.

Case

Houses the watch movement, keeping out dust and damp. Different case shapes and designs determine the visual appeal of the watch. A larger style (boyfriend) case is still very popular with women for everyday wear.

Casing Ring

The ring fitted around the movement to fill the gap between the movement and the case.

Ceramic

A high-tech material made from aluminium and zirconium oxides. Currently a popular material for the manufacture of watch cases and other decorative elements.

Chronograph

A watch with separate functions and sub dials designed to measure an interval of time. Can be used to measure durations from 1/5th up to 1/1,000th of a second in very advanced models.

Chronometer

A timepiece that has been certified to meet high standards of accuracy by the COSC (Controle Officiel Suisse des Chronometres) in Switzerland.

Cloisonné

An enamelling technique where the outline of the design is formed by placing thin wires onto the surface to be decorated.

Clous de Paris

Literally meaning ‘nails of Paris’, a style of Guilloche pattern used on a dial which depicts hollowed lines that intersect to form pyramid shapes (it is also the name of a watch collection created by Longines).

Clutch

A coupling in the mechanism that temporarily connects two rotating parts. For example, the multiple functions performed by the crown, setting the time and winding the mainspring.

Column Wheel

Responsible for coordinating the start, stop and return to zero functions of a chronograph.

Complication

Any additional function other than the basic functions of timekeeping. Examples of complications include chronographs, minute repeaters, moon phase and world timing.

Countdown timer

Kinda what is says on the tin – a device for counting backwards.

Crown

Not remotely royal, the crown is used to wind the watch and set the time and calendar.

Crystal

The thin sheet of glass or other synthetic material to protect the watch dial. Most often this is a Sapphire crystal but can also be mineral crystal or acrylic crystal.

Cuvette

A cover inside the case back to protect the movement against dust.

D

Dead Seconds

A hand that jumps forward when the second has elapsed, typical in a quartz watch but incredibly difficult to replicate in a mechanical watch.

Dial

The ‘face’ of the watch indicating the hours, minutes, seconds and other functions.

Digital

A watch in which the time is indicated by digits, rather than hands, how very 1980’s!

Dual Time

A watch that simultaneously gives the time in two time zones, a useful function for travellers or those who liaise with an overseas office at work.

Dynamograph

Developed specifically by Audemars Piguet to indicate the amount of tension in the mainspring. As long as the Dynamograph hand remains in a designated zone the watch will be supplied with the optimum amount of energy.

E

Ebauche

An unfinished watch movement to be assembled into a finished watch elsewhere.

Escapement

A mechanism fitted between the gear train and the balance to regulate the oscillations of the balance.

F

Face

See: Dial.

Feuille

A hand taking the form of a leaf.

Flange

The part inside a watch case which supports the movement.

Fly Back

A hand on a chronograph that can be reset to zero with one push, literally ‘flying back’.

Folding Buckle

A buckle which unfolds when opened, but will hold the strap in place to prevent the watch slipping over the hand; should it accidentally come open whilst gesticulating wildly over a glass of wine.

Foudroyante (Jumping Seconds)

A chronograph hand that makes one rotation every second, pausing four, five even eight times to indicate quarters, fifths or eighths of a second.

Frequency

The number of oscillations per second, measured in Hertz (Hz). The higher the frequency the more accurate the watch. A quartz watch vibrates at a frequency of 32,768 Hz (abbreviated to 32 KHz).

G

Gear Train

The system of gears in a watch used to transmit power and motion through toothed wheels.

Gears

A set of wheels in which the movement of one engages the other.

Grand Sonnerie

A watch that strikes the hours and quarters, and repeats the hour at each quarter. It is sometimes combined with a minute repeater.

Greenwich Mean Time (GMT)

Mean time at the Royal Observatory in Greenwich, the prime meridian of the world.

Guilloche

A decorative engraving technique using a precise and intricate repetitive pattern, often used on watch dials.

H

Hairspring

See: Balance Spring.

Hand

A thin shaped marker which rotates around the dial, most watches have three hands to indicate the hours, minutes and seconds.

Horology

The science of measuring time and the study of timepieces.

I

Incabloc®

Shock absorbing system to protect the watch from breaking if dropped.

Independent Seconds

A hand in the centre of the dial driven by a separate train to the hours and minutes; making one jump forward every second.

Inverted Calibre

A watch whose dial is on the side with the visible movement, rather than on the bottom plate.

Isochronal / Iscochronism

The oscillations of the balance are isochronal, meaning the watch runs at the same rate whether fully or only partially wound.

J

Jewels

Generic term for the rubies in a watch movement. Jewels serve as bearings for the gears to reduce friction and wear.

Jumping Hour

A watch that displays the hour through an aperture in the dial, which jumps forward every 60 minutes.

Jumping Seconds

See: Foudroyante (Jumping Seconds).

L

Large Date

See: Big Date

Lever

Part of the escapement and shaped like a ship’s anchor, it has a dual function; transmitting energy from the spring to the balance and controlling the movement of wound gears.

Liquid Crystal Display (LCD)

The continuous display on an electronic watch comprised of numerals made up of dark bars against a lighter background.

Lug

Extending from the watch case to which the strap or bracelet is attached.

Luminescent

The ability to emit light rays. Many watch brands use LumiNova®, a non-radioactive luminescent substance to coat numerals and markers. LumiNova® soaks up light and reflects it, causing it to glow in darkness.

M

Mainspring

Stores and provides energy to drive the watch.

Marker

The term used to describe a symbol often used instead of numerals on a dial.

Mechanical movement

Driven by the mainspring, a mechanical movement is a configuration of mechanical parts including the balance, gears and escapement; designed to perform specific functions.

Microsecond

A unit of time; equivalent to one millionth of a second.

Moon Phase

A complication displayed through an aperture in the dial showing the current phase of the moon.

Mother-of-Pearl

Commonly used on women’s watch dials, natural mother-of-pearl is the iridescent surface from the inside of certain shells.

Movement

The inner mechanism of a watch responsible for keeping time. Movements are either mechanical (some of them are automatic) or Quartz.

P

Pavé

A group of gemstones set closely together and covering an entire surface- beautifully intricate or major bling- either way, a Pavé watch will leave your purse considerably lighter!

Perpetual Calendar

A calendar that automatically takes into account the varying number of days in the month and leap years- seriously clever stuff.

Plate

A watch has both front and back plates. The internal parts are held between the two.

Power reserve indicator

A visual indicator of the remaining energy in the main spring. Essentially referring to the length of time a watch will function before it must be wound again.

Pulsometer

Sometimes incorporated on the dial of a sports watch to measure the number of heart beats per minute.

Push button

As it sounds…a button that performs a function when pushed eg start/stop a chronograph.

PVD

An acronym for Physical Vapour Deposition- the means of depositing a thin film of metal onto a surface. Mainly used upon dials but sometimes on other external parts of a watch. Often described as PVD coated.

Q

Quartz

Also called ‘Rock crystal.’ Used as a regulating organ in watches due to its high frequency vibrations (32KHz) when placed under an electric current provided by a battery.

R

Rate

A term used to describe the regularity of a watch. Its daily rate is the amount of time a year a watch gains or loses over a 24 hour time period compared to a reference timepiece.

Regulator

In a mechanical watch this refers to the balance and spring, whose function is to count time. In an electronic watch it could be a quartz crystal or a tuning fork.

Repeater

(Also see: Grand Sonnerie) A watch that audibly sounds to denote the time when the wearer pushes a button. Most common ‘complication’ is a minute repeater that indicates the time to the nearest minute by striking a gong. Caution; may cause irritation.

Retrograde

A scale shown on the dial which may represent an hour, minute, seconds or calendar function. A hand moves across the scale and when reaching the end of the scale and when reaching the end of its cycle, returns to zero to begin again.

Rhodium plating

A thin protective or decorative coating used on metal to provide a shiny appearance and to harden the surface.

Rotating Bezel

See: Bezel.

Rotor

A disc in the movement of an automatic watch that freely rotate with the wearer’s movement to wind the mainspring.

S

Self-Winding

See: Automatic.

Shock Absorber

A small spring that holds the balance staff jewel in place and prevents it from breaking under shock. The majority of  watches now use the Incabloc® system.

Simple Calendar

A watch which shows the number of days in each month, some calendars (also called day/date) may also display the name of the month. A simple calendar does not automatically take months with less than 31 days into account and therefore must be adjusted 5 times a year.

Skeleton Movement

A movement which has been cut away to expose its main parts and is housed in a case with a transparent  front and/or back so that the wearer can view the movement.

Slide Rule

A device used on chronograph watches to allow the wearer to  perform calculations.

Spring Bar

The bar used to fix a watch strap to the case lugs.

Subdial

Refers to any additional dial on the watch face which may be used for many purposes, including seconds, chronograph or date.

Subsidiary Seconds

A small subdial showing seconds, generally positioned at 6 0’clock; as opposed to a sweeping second hand.

T

Tachymeter

An instrument for measuring speed. When used in watchmaking, a chronograph with a scale for reading seconds. Often used on aviation watches and shown in km per hour.

Telemeter

A chronograph featuring a telemeter scale which is used to measure distances. Distances are calculated on the basis of speed of sound through the air.

Tourbillon

Invented by AL Breguet in 1801, a system to compensate for errors of rate caused by gravity. The escapement is mounted on a rotating platform which revolves once a minute to eliminate timekeeping errors.

Train

See: Gear Train.

U

Unidirectional Rotating Bezel

See: Bezel.

V

Vibration

The movement of the pendulum , or oscillating body (balance) between two extreme positions. A mechanical watch generally makes five, six or eight vibrations per second, equivalent to an average of 3Hz, with the most advanced  making 10 vibrations per second. The higher the vibration, the greater the precision. In comparison, a quartz watch has 32KHz.

W

Water Resistence

See: Atm.  Diving watches are designed  to be worn underwater at a depth of at least 100 metres.

Winding Mechanism

Used to tighten the mainspring. This is done externally using the crown, which is attached to the winding stem.

World Time

A watch that indicates the time  in different world cities, very useful for the global business traveller.