Watch Glossary
Learn about the different parts of a watch, from the intricate mechanisms and types of materials used, to the various complications and more.
A
Acrylic Crystal
A type of inexpensive plastic – it is soft and flexible, so can withstand small impacts and can allow shallow surface scratches to be buffed out.
Alarm
A watch complication that sounds a signal at a predetermined time or at regular intervals.
Aperture
A small window within the dial of a watch, displaying information such as the date.
Analogue Display
A watch that displays the time using the hour and minute hands on a dial.
Anti-Magnetic
A device that is not affected by magnetic fields.
Ardillon Buckle
A standard two-piece buckle used to secure a leather watch strap around the wrist.
Atmosphere (ATM)
A unit of measurement used to indicate the water resistance of a watch.
Automatic Movement / Automatic Winding
Watches with automatic movements do not need to be regularly wound. They have a mechanism that winds automatically when you are wearing the watch. This is triggered by the movement of your wrist.
Learn more about the different types of movements on our Watch Movements page.
B
Balance Spring
A very small spring in a mechanical watch that returns the balance wheel back to its neutral position.
Balance Wheel
A part of a mechanical watch which oscillates and divides time into equal portions.
Battery Reserve Indicator
A function on some quartz watches which indicates when a battery is nearing the end of its life. This is most often indicated by a variation in the movement of the hands on the watch – they jump 2-4 seconds, depending on the make and model. Also known as an End of Life indicator (EoL).
Bezel
The ring round the case of the watch that can secure the crystal. They can be functional for diving or timing, but they can also be decorative.
Bi-directional Rotating Bezel
A bezel that can be rotated either clockwise, or counter-clockwise, to keep track of elapsed time or make mathematical calculations.
Bracelet
C
Cabochon Crown
A crown set with a precious or semiprecious stone. See also Crown.
Calendar
A watch feature displaying the day of the month, often on the subdial, or a scale on the outside edge of the watch dial.
Caliber
Also known as a calibre, the caliber is a term used to describe the size or style of a watch movement.
Cambered
A curved or arched dial or bezel.
Carat (Karat)
A unit of gold fineness (and gemstone weight). 24K is pure gold, whereas 18K gold is 75% pure.
Case
The case around the watch that protects the watch movement.
Case Back
The underside of the watch that lies against the wrist. See also Exhibition Case Back.
Chronograph
A stopwatch feature built into the movement.
Chronometer
An instrument for measuring time very accurately – a standard set by the Official Watch Institute of Switzerland (Contrôle Officiel Suisse des Chronomѐtres, COSC). A chronometer is known to be 99% accurate over a fifteen day period, in a variety of simulated wearing positions and different temperatures.
Complication
An additional feature on a watch beyond the display of the time.
Crown
The mechanism used to make adjustments to the watch functions, like changing the date and time. It is also used to wind the movement on mechanical watches.
Crystal
The clear part of the watch that covers and protects the face of the watch. The three main types of material used in watchmaking are synthetic sapphire, mineral and acrylic.
Cyclops
D
Day-Date
A complication that indicates the day of the week, as well as the date.
Deployant Buckle
A folding metal buckle, designed by Cartier in the early 20th century. It is considered more secure, as if the buckle opens up, the watch is still attached to the wrist.
Dial
The dial consists of the hour marker and hands on the watch face – these are the parts which display the time.
Diver’s Watch
A watch with excellent water resistance. They usually have a unidirectional diver’s bezel to assist in recording dive time.
E
End of Life (EOL)
A function on some quartz watches which indicates when a battery is nearing the end of its life. This is most often indicated by a variation in the movement of the hands on the watch – they jump 2-4 seconds, depending on the make and model. Also known as a Battery Indicator.
Exhibition case back
An exhibition case back is a transparent material added to the back of a watch to display its inner workings.
F
Face
The front of the watch containing the dial.
Flyback / Flyback Hand (Retour en vol)
A seconds hand on a chronograph that can be stopped independently and then made to catch up (“fly-back”) with the other constantly moving seconds hand.
Frequency
The number of vibrations a second, in hertz (Hz).
Fusee
A device to regulate the flow of power from the mainspring using a chain (or fusee), which reduces the inertia of the mainspring when fully wound and increases inertia when the mainspring is nearing the end of its power reserve.
G
Gasket
Gaskets seal the case back, crystal and crown from water infiltration on water resistant watches.
Gold
A precious metal used in alloys to make jewellery, bracelets and watches.
Greenwich Mean Time (GMT)
A universal standard time, the starting point from which all other 23 time zones are set.
Guilloché
H
Hands
An indicator anchored at the centre of the watch that moves around the dial to point at the hour, minute, or second. Watches usually have three hands to show the hours, minutes and seconds.
Helium Escape Valve
A depressurising function on a diver’s watch which allows the helium to slowly escape from the watch as the diver ascends to the surface.
Horology
The art and science of watchmaking.
Hour Markers
I
Indestructible
The goal for watchmakers, resulting in the development of new materials and watches that are not easily damaged or destroyed.
J
Jewels
Synthetic sapphires or rubies that act as bearings for gears in a mechanical watch. Most watches with mechanical movements will contain at least 17 jewels.
K
Karat (Carat)
L
Lugs
The lugs are the case attachment which allows the strap or bracelet to be attached to the watch case.
M
Mainspring
The part of the watch that stores the power that is released to the escapement.
Manual / Manual Winding
A watch with a movement that needs to be wound using the crown to provide power to the mainspring.
Learn more about winding and setting your watch on our Watch Maintenance page.
Mechanical Movement
A movement based on a mainspring that is wound by hand. When wound, it slowly unwinds the spring in an even motion.
Learn more about the different types of movements on our Watch Movements page.
Military Time (24-hour time)
Time measured in 24-hour segments.
Mineral Crystal
A type of watch glass that has been tempered to increase its scratch resistance.
Minute Repeater
On command a minute repeater chimes the hours, quarters and minutes past the last quarter, allowing you to hear the time audibly.
Moon Phase
A device for showing the age or phase of the moon on a coloured disc.
Movement
The movement is the heart of any watch. Its purpose is to turn stored energy into regulated time and it powers the watch hands. There are three main types of movement: mechanical, automatic mechanical and quartz.
Learn more about the different types of movements on our Watch Movements page.
N
Numerals
The group of figures or symbols denoting a number around the edge of the watch dial, to indicate the time.
O
Oscillation
P
Perpetual Calendar
A movement showing the day, date, month and leap year. When set, this watch will show the correct date, including the long and short months and also February in a normal year, and also in a leap year.
Plating
A thin layer of metal used to coat the base metal of a watch.
Platinum
A precious, silvery-white metal; it is hypoallergenic, strong and tarnish resistant, making it a popular choice for jewellery and watches.
Power Reserve
The amount of time a watch will operate for when fully wound and left off the wrist.
Pusher
The pusher is similar to the crown; it is a button on the side of the watch that controls functions like the chronograph or date adjustment.
Q
Quartz
R
Ratchet Bezel (Rotating Bezel)
A bezel that can be rotated clockwise or anti-clockwise.
Rattrapante (Split-Second Chronograph)
A chronograph that has a double layered second hand that can be split in two, in order to facilitate the timing of two events over a 60-second period. Useful for lap times at a sporting event for example.
Retour en vol (Flyback)
A seconds hand on a chronograph that can be stopped independently and then made to catch up (“fly-back”) with the other constantly moving seconds hand.
Rose Gold
A pink coloured gold, it contains the same materials as yellow gold, but with a higher concentration of copper in the alloy.
Rotor
Also known as the Oscillating Rotor, Oscillating Mass, or Oscillating Weight, the rotor is the part of an automatic watch that is responsible for winding the mainspring.
S
Sapphire Crystal
A material used to make the glass of a watch that is very resistant to scratches.
Screw-Down Crown / Screw Locking Crown
A type of crown that can be screwed down into the case to help protect against dust and aid water resistance.
Shock Resistance
A watch’s ability to withstand an impact, such as being dropped.
Split-Second Chronograph (Rattrapante)
A chronograph that has a double layered second hand that can be split in two, in order to facilitate the timing of two events over a 60-second period. Useful for lap times at a sporting event for example.
Strap
The strap is commonly a leather or rubber attachment that secures the watch to the wrist. Metal attachments are known as bracelets.
Subdial
The subdial is a small dial set into the main watch dial. It is used to display additional complications like a chronograph or seconds.
SuperLuminova
A modern luminous material used to improve visibility of the dial marking and hands in darkness.
Sweeping Seconds Dial
A second hand that is mounted in the centre of the dial, instead of a subdial, and “sweeps” the entire dial of the watch.
T
Tachymeter / Tachometer
A scale sometimes inscribed around the rim of an analogue watch with a chronograph. It can be used to measure the speed at which the watch wearer moves.
Tang
A belt-style buckle. See also Ardillon Buckle.
Titanium
A metal that is stronger and lighter than stainless steel, and which is increasingly used to make watches.
Tonneau Watch
A watch shaped like a barrel with two convex sides.
Tourbillon Escapement
A type of escapement designed to rotate once every 60 seconds, which houses the hairspring and pallet wheel. The principle is that the effects of gravity on the hairspring in the upright position are eliminated.
U
Unidirectional Rotating Bezel
Typically called a diver’s bezel to measure a small amount of time under one hour. Often used for timing dives and showing the first 15 minutes in a highlighted fashion.
V
Vorsprung durch Technik
A German phrase, best translated in English as ‘progress through technology’, or ‘advancement through technology’.
W
Water Resistance
A watch marked as water resistant can usually withstand splashes of water. The water resistance will indicate the depth that a watch can be worn underwater.
Learn more about water resistance on our Watch Maintenance page.
White Gold
An 18K alloy of yellow gold with nickel or similar metal, giving a more silver-coloured appearance.
Winding
The action of tightening the mainspring of a watch. This is done by turning the crown on a manual watch, or automatically by the motion of the rotor in an automatic watch.
Learn more about winding and setting your watch on our Watch Maintenance page.
X
X-ray skeleton watches
A watch with a transparent dial, showing the inner workings and mechanical movement of the watch.
Y
Yellow Gold
Z
Zenith
A watch brand and, more generally, the watchmaker’s philosophical quest for perfection.
Watch Guides
Find out more about watches.
Watch CLP Page
