Watch Glossary

The Watch Superstore posted this on 31 Jul 2015

Glossary Of Terms:


Alarm

Alerts you to a preset time with a noise or vibration.

Altimeter

Measures altitude / height above sea level. A mountaineering essential.

AM/PM Indicator

See Day/Night Indicator

Analog/Digital (Duo) Display, or  Anadigi

Displays time through an analogue display (with hour and minute hands) and a digital display (graphical digits). Also known as Duo Display or AnaDigi.

Analogue

Uses a dial and hands to display the time.

Annual Calendar

Displays the date. Can display anything from Day and Date to Moonphase. See Perpetual Calendar, Moonphase

Aperture

Displays certain details like the date on the dial of some watches.

Auto Repeat Countdown Timer

Counts down to a preset time and then re-starts as soon as the preset time elapses.

Automatic Winding Movement

Operates in the same way as a mechanical manual wind watch with the addition of the Rotor. This is a weighted pendulum that is attached to the back of the movement and spins around the inside of the watch, "automatically" winding it when you move your wrist with normal use. This means that you don’t need to wind your watch, except for once every month or so. If you have an automatic watch that’s stopped, we recommend that you manually wind it about forty times to get the watch back to its full reserve when you wear it again. When you remove your watch, it will then continue to function for the time specified in the manual. This varies but is usually around forty hours.

Balance Spring

Also known as a Hairspring because of its size, it’s a very fine spring found in mechanical watches that causes the balance wheel to recoil, regulating its timekeeping.

Balance Wheel

Controls the watch’s accuracy.

Barrel

Holds the Mainspring in a mechanical watch and controls its Power reserve. Watches with a Double-Barrel have a much longer power reserve.

Bezel

Used to measure time increments, this is a ring found on the top side of the case around or sometimes beneath the crystal.  Available as uni-directional or bi-directional, bezels can be used to begin timing an event at any time by aligning the number twelve at the start point. Fixed bezels are also available. See Uni-Directional Turning Bezel, Bi-Directional Rotating Bezel, Tachymeter Scale

Bi-Directional Rotating Bezel

This type of bezel can be turned clockwise and anti-clockwise so that it has great flexibility to begin timing and is used for tracking elapsed time.

Bracelet

This is the strap that keeps the watch face on your wrist. A bracelet is usually made from metal links that can be adjusted to fit your wrist perfectly.

Breguet Spring

This is named after Abraham-Louis Breguet, who created a change in the hairspring in 1795. As this spring expands and contracts, it crushes up on either side and therefore disrupts the balance but Breguet’s solution of reducing the size of the last coil and raising it up improves the watch workings and reduces the abrasion on the balance pivots.

Bridge

This part is fixed to the main plate of the watch to form the frame of a watch movement.

Calendar

This displays the date of the month or the day of the week and the year.

Cambered

This term describes a Domed or Arched Crystal

Caliber or Calibre

A term that refers to the movement. For over two centuries, the calibre of a movement has denoted the position and size of the wheel train and the barrel.

Case

This is what the watch’s parts are contained within. Usually made from metal like stainless steel, more expensive metals like gold are sometimes used on more expensive watches.

Chronograph

This refers to a watch that has a stopwatch function. It displays the time as well as measuring and displaying elapsed time. Usually, this is operated by two buttons on the edge of the case which start, stop and reset the chronograph. See Split Seconds Chronograph a.k.a. Rattrapante, Mono (Single) Pusher Chronograph, Fly-Back Chronograph

Chronometer

This is a term only used to describe a watch that’s been rated by the Swiss testing laboratory, Contrôle Officiel Suisse des Chronomètres. During testing, mechanical movements that are accurate to plus or minus 4 - 6 seconds in a day are awarded a chronometer certificate. Quartz movements must be accurate to plus or minus 0.2 seconds in a day, because these don’t vary based on position & temperature. See Quartz Movement, Mechanical Movement, COSC.

Complication

This refers to a watch that has more than just the ability to display the time. This could be an alarm or calendar, etc.

COSC

This is the acronym for Contrôle Officiel Suisse des Chronomètres. See Chronometer

Countdown Timer

Tells you how much of a preset time has passed.

Crown

Also known as a winder or winding stem, this is what is used to set the time (hands) on your watch. It’s usually a little knob on the edge of the case and can also be used to wind the mainspring of a mechanical watch. See Screw-Down Crown, Winding Crown

Crystal

The clear, often glass or plastic and sometimes scratch-resistant sapphire crystal, cover on a watch that covers the dial.

Day/Date

This kind of watch displays the day and date.

Day/Night or AM/PM Indicator

This function tells you whether the time is before or after 12 noon and is usually found in watches with a World Time Display, for example.

Deployment Buckle

This expandable buckle fastens the strap around your wrist securely. It allows the watch to slip on and snap shut, therefore reducing strain on the strap itself.

Digital Display

Uses numbers or digits to display the time, rather than hands on a watch face. A popular digital display type is Liquid crystal display (LCD).

Dual Time

Shows local time and in another time zone. Usually displayed by an additional hour hand, it is sometimes shown in a smaller dial within the main watch face. See GMT, World Time Display.

Duo Display

This displays the time in analogue format with hour and minute hands as well as digitally. See Analog/Digital Display

Dial

The face of the watch where you read the time.

Elapsed Time Rotating Bezel

Used to keep track of set periods of time this is a graduated, rotating bezel that can be rotated so that you can align the zero of the bezel with the watch's minutes or seconds hand and then the elapsed time can then be read from it.

EOL

This simply stands for End Of Life and refers to the battery in a Quartz watch.

Engine Turning/Turned

Also known as Guilloche, this ancient technique is still used by watchmakers today to engrave delicate designs onto metal watch parts.

Equation Of Time or EOT

This complication displays the difference of true solar time dictated by nature and man’s version, mean solar time. We think of days being 24 hours long but in fact, because of the way that the earth orbits around the sun in an elliptical manner on a tilted axis, there are only four days in a year when the day is 24 hours long:  April 15th, June 14th, September 1st and December 24th. For the rest of the year, the days are all shorter or longer and our “mean” time is simply an adjusted version of this.

Escapement

This device effectively moves the watch hands by creating the impulses to maintain the oscillations of the balance wheel or pendulum.

Fly-back Chronograph

This is a chronograph that immediately restarts when it’s brought back to zero.

Function

This describes something that a watch has, for example, a countdown timer. These are also known as complications.

Gear Train

These gears transmit power to the escapement from the mainspring.

GMT Time Zone

Greenwich Mean Time (GMT) is also known as Zulu Time and UTC (Universal Time Coordinated) and it is the international time standard by which all World Time is set. Agreed in 1884, it remains the same throughout the year and is not impacted by Daylight Saving Time. See Dual Time, World Time

Gold Plating

This is when a thin layer of gold is used to cover something. In terms of watches, this is usually in relation to a gold plated case or bracelet.

Guilloche

Guilloche is also known as Engine Turning and is a delicate engraving technique that’s been used for centuries to etch a design onto metal. See Engine Turning

Hairspring

This is a really fine spring that’s found inside mechanical watches. It is shortened and lengthened to regulate the watch’s timekeeping. See balance spring.

Helium Escape Valve

Used on professional diving watches, this one way valve releases pressure during the decompression that occurs during  dive. Helium is used in breathing mixes used by divers but as they dive deeper whilst using a diving bell and decompress the helium, it will seep through into the watch because of its tiny molecules. This can cause the crystal of the watch to pop out.

Horology

This is the science of time measurement and includes the construction and design of timepieces.

Index Hour Marker

This is simply an indicator on an analogue watch that is often used in place of a number or numeral.

Jewels

These are faux gemstones are used as bearings for gear trains and can reduce friction.

Jump Hour/Minutes

This is a display that shows a number that changes on the hour or minute, rather than a hand that rotates continually. The sun, our first means of understanding the notion of time, appears to move around and so a hand on a dial seems like a natural way of telling the time but a jumping display is an alternative way to indicate time. Each new indication is instantaneous and on each hour, the mechanism causes the numbered disc to make one jump forward.

Lap Timer

This function enables you to time parts of a race, for example, a relay. It’s a function within a chronograph and when a lap is completed, the timer stops and returns to zero, ready to time the next lap.

Lever Escapement

This is when the wheel teeth are locked and unlocked by the two pallets that make up the lever. When the balance engages the other end of the lever, the escape teeth that slide on the inclined pallets lift the lever to move the balance.

Liquid Crystal Display (LCD)

Liquid crystal display or LCD as it’s commonly known, is a type of digital display. It’s formed by liquid that’s formed into seven segments and hel

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