If you are looking to buy a new watch or sell your watch, or just want to learn more about the terminology, then this glossary is for you! In this post, we will define common watch terms and explain what they mean. By understanding the language of watches, you will be able to make a more informed purchase and appreciate the beauty of these timepieces.
A
Alarm
A function on a watch that emits a sound or vibration at a predetermined time.
Altimeter
A device that measures altitude, typically used by mountaineers and pilots.
Amplitude
The measure of the maximum angle through which the balance wheel rotates, indicating the health and accuracy of a mechanical watch.
Analog
A watch with an analog display uses hands and hour markers to show the time. This is the most common type of watch.
Aperture
An opening in the dial of a watch that typically displays information such as the date or day of the week.
Automatic
An automatic watch is powered by the movement of the wearer’s body. These watches are convenient because they do not require winding, but they may need to be serviced more frequently than manual watches.
B
Balance
The balance is a wheel in a mechanical watch that oscillates back and forth to keep time.
Balance Spring (Hairspring)
A small spring in the balance wheel that controls the oscillations of the balance, crucial for accurate timekeeping.
Barrel
The barrel is the housing for the mainspring in a mechanical watch. It stores energy to power the watch.
Bezel
The bezel is the ring that surrounds the dial of the watch. It can be used to track time or measure distance.
Breguet Overcoil
A special type of hairspring invented by Abraham-Louis Breguet that improves the accuracy of a watch by reducing the effects of gravity.
C
Calibre
The calibre is the internal mechanism of a watch that keeps time. It is also used to refer to the size of a watch.
Chronograph
A chronograph is a type of watch with a stopwatch function. These watches are often used by athletes to time their events.
Clasp
The mechanism that secures the strap or bracelet of a watch on the wrist, commonly found as deployant (folding) or tang (pin) buckles.
Complication
A complication is any additional function on a watch beyond telling time. Common complications include a calendar, chronograph, or alarm.
COSC Certification
A certification granted by the Swiss Official Chronometer Testing Institute (Contrôle Officiel Suisse des Chronomètres) to high-precision watches that meet stringent accuracy standards.
Côtes de Genève
A decorative finish featuring parallel lines, typically found on the movement plates of high-end watches.
Crown
The crown is the knob on the side of the watch that is used to set the time and date. It is also used to wind a mechanical watch.
Crystal
The crystal is the clear cover that protects the dial of the watch. It is usually made of glass or synthetic sapphire.
D
Dial
The dial is the face of the watch where the time is displayed. It can be analog or digital, and often has other features such as a date window or stopwatch function.
Digital
A digital watch displays the time using numbers or an LED display. These watches are often more sporty in design.
E
EOL (End of Life Indicator)
A feature in quartz watches that indicates when the battery is nearing depletion, usually by causing the seconds hand to move in increments of two or more seconds.
Escapement
The escapement is a device in a mechanical watch that regulates the release of energy to the balance wheel. This ensures that the watch keeps accurate time.
F
Flyback
A flyback chronograph is a type of chronograph that can be reset to zero and restarted with one push of the button. This is convenient for timing multiple events.
G
Gasket
A seal used in a watch to make it water-resistant, typically made of rubber, nylon, or Teflon.
Guilloche
Guilloche is a type of decoration on a watch dial that consists of intricate patterns.
H
Hand
The hand is the part of the watch that points to the time on the dial. There are typically three hands on an analog watch: hour, minute, and seconds.
Helium Escape Valve
A feature found on professional dive watches that allows helium to escape during decompression, preventing the crystal from popping off.
I
Incabloc
A brand name for a shock protection system used in mechanical watches to protect the balance wheel pivots from damage.
J
Jewels
Jewels are used in watch movements to reduce friction and wear. They are typically made of synthetic sapphire or ruby.
K
Kinetic
A kinetic watch is powered by the movement of the wearer’s body. These watches are convenient because they do not require winding, but they may need to be serviced more frequently than manual watches.
L
Lugs
The lugs are the horns that protrude from the top and bottom of the watch case. They are used to attach the strap or bracelet.
Lume
A luminescent material applied to the hands, markers, or dial of a watch to make it readable in low light conditions.
M
Mainspring
The mainspring is the power source in a mechanical watch. It is a coiled spring that is wound by the crown.
Manual
A manual watch requires the user to wind the watch periodically to keep it running. These watches are considered more traditional and often have a longer lifespan than other types of movements.
Minute Repeater
A complication that chimes the hours, quarters, and minutes on demand, activated by a slide or pusher on the watch case.
Micro-Rotor
A smaller version of a standard rotor in an automatic watch, often integrated into the movement rather than being placed on top of it.
Movement
The movement is what powers a watch and keeps time. There are three types of movements: manual, automatic, and quartz.
P
Perpetual Calendar
A highly complex complication that displays the day, date, month, and leap year cycle, adjusting automatically for months with different lengths and leap years.
Power Reserve Indicator
A power reserve indicator is a feature on some watches that shows how much power is left in the watch. This is useful for knowing when to wind the watch or when it needs to be serviced.
Q
Quartz
A quartz watch uses an electronic oscillator to keep time. These watches are the most accurate and require little maintenance.
R
Repeater
A repeater is a type of complication that allows the user to hear the time. This is done by activating a lever or button on the watch.
Rotating Bezel
A rotating bezel is a bezel that can be rotated. This feature is often used on dive watches to keep track of elapsed time underwater.
Rotor
A semi-circular weight in an automatic watch that spins with the motion of the wearer’s wrist to wind the mainspring.
S
Screw-Down Crown
A type of crown that screws into the watch case, providing additional water resistance.
Second Time Zone
A second time zone is a feature on some watches that allows the user to keep track of two time zones simultaneously. This is useful for travellers who need to know the time in multiple places.
Shock Absorber
A system within a mechanical watch designed to protect the movement from shocks, often using jewels or special springs.
Skeleton
A skeleton watch is a type of watch that has a transparent dial or case back. This allows the user to see the inner workings of the watch.
Solar
A solar watch is powered by light. These watches are convenient because they do not require winding, but they may need to be serviced more frequently than manual watches.
Spring Drive
A technology developed by Seiko that combines mechanical movement with an electronic regulator for exceptional accuracy.
Stopwatch
A stopwatch is a type of complication that allows the user to time events. This is done by starting and stopping the timer with a pusher on the watch.
Strap
The strap is what attaches the watch to the wrist. It can be made of leather, metal, or rubber.
Subdial
A subdial is a small dial on the watch face that typically displays the seconds or another function.
Superlative Chronometer
A superlative chronometer is a type of watch that has been certified by COSC (Contrôle Officiel Suisse des Chronomètres) to be accurate to within + or – 0.0000001 seconds per day.
Swan Neck Regulator
A fine adjustment mechanism used in high-end mechanical watches for more precise regulation of the balance wheel.
T
Tachymeter
A tachymeter is a type of complication that allows the user to measure speed or distance based on time. This is done by starting the timer at a specific point and stopping it at another point.
Tonneau
A watch case shape resembling a barrel, with rounded sides and a curved profile.
Tourbillon
A tourbillon is a type of complication that helps to improve the accuracy of a watch by compensating for the effects of gravity. This is done by housing the escapement in a rotating cage.
Triple Calendar
A complication that displays the day, date, and month.
U
Unidirectional Rotating Bezel
A unidirectional rotating bezel is a bezel that can only be rotated in one direction. This feature is often used on dive watches to keep track of elapsed time underwater.
V
VPH (Vibrations Per Hour)
A measure of the frequency of a watch’s movement, indicating how many oscillations the balance wheel makes per hour. It is directly related to the accuracy of the watch.
W
Watch Case
The watch case is the housing that holds the movement and other components of the watch. The case is usually made of metal, but can also be made of plastic or wood.
Water Resistance
Water resistance is a measure of how well a watch resists water damage. Watches are usually rated by their depth rating in metres or atmospheres (ATM).
Winding
Winding is the process of tightening the mainspring in a watch to keep it running. This must be done periodically for manual watches.
Z
Zinc Alloy
A type of metal often used in more affordable watch cases, which is lighter and more cost-effective than steel.
