Watch Parts – A Glossary Of Terms & Functions


In even the most simplistic mechanical watch, you can expect to find an excess of 100 working parts that fit together perfectly, crafted to keep time while looking good on your wrist. But do you know how these parts come together, and do you get confused by the jargon of the watch world? Read on to discover what’s hidden within your mechanical timepiece.

A horologist at work, adjusting various watch parts
A horologist at work, adjusting various watch parts

Watch Jargon can be Confusing!

The important thing to note with a timepiece is that although the movements may seem overwhelmingly intricate, each part has its purpose and function and no watch can work properly without each of its components. It’s for this reason, that we’re proud to present you with a glossary of parts and points which will hopefully allow you to better understand how your watch works and what to ask for when buying your next timepiece.

Raphael having a glass of wine and reading a book by the fireplace

Be Your Own Expert

One of the most common mistakes made when purchasing a watch is to rely solely on the guidance of the salesperson at a local jewelry store. Unless they specialize in luxury watches or you’re at an authorized dealer for a brand like Breguet or Rolex, chances are they only have an average amount of knowledge about what lies beneath the watch face. They may know where the watch is from or whether it’s a mechanical, automatic, or quartz movement, but don’t trust they are an expert until you’ve built a foundation of understanding first.

The “0-9” of Watch Parts, Pieces and Functions

12 or 24-Hour Register:

The register (often referred to as a recorder) is a sub-dial usually appearing on the front face of a chronograph that can record time periods of up to 12 or 24 hours.

30-Minute Register:

Like the 12/24 register, the 30-minute is also a sub-dial on a chronograph that can chart periods of up to 30 minutes at a time.

The “A” of Watch Parts, Pieces and Functions

Acrylic Crystal:

Acrylic crystal is a type of crystal on the front of your watch (often called the glass or window), that protects the dial and face of the watch. One thing to take note of is that often inexperienced watch salesmen looking for a quick sale may refer to this type of crystal as a hesolite crystal in an attempt to make it sound more elegant.

Orient Bambino Watch
Orient Bambino Watch with a domed crystal

However, while acrylic is known for having minimal glare under bright light, it’s a much less expensive crystal than that of mineral or sapphire. Due to its flexibility, it has a tendency to resist shattering when hit or impacted, however, it is still much less durable than its more expensive counterparts.


Many people often wonder why their watch says “adjusted” on it or why the salesman opted to use that as a selling feature. Typically, this refers to the tests the watch undertakes while being assembled. To ensure a quality timepiece with minimal disruption or loss, the watchmaker will calibrate it using at least nine adjustments which include step-up, stem-down, stem-left, stem-right, face-down, face-up, isochronism, heat, and cold. This ensures that when the watch is taken home it can work flawlessly in various environments.


Most people understand the purpose of an alarm and that’s simply to alert you of a specific pre-set time. An alarm can be on both quartz and mechanical timepieces, where the mechanical ones typically provide an extra hand for setting it. Inside the movement, there will be a second mainspring that activates a tiny component causing a weight to vibrate back and forth which causes the noise or vibration at the pre-set time.


Typically found in flight or pilot watches, it’s similar to the components found in the cockpit of an airplane. As one may have guessed, the altimeter’s job is to measure altitude (height above sea level) which records ascent and descent by responding to changes in barometric pressure. While this function is important for pilots, it also serves useful for mountain climbers, skydivers, or anyone in need of measuring height.

AM/PM Indicator:

Also called a night and day indicator, the AM/PM function allows the user to determine the time of day on a 12-hour analog or digital watch.

Analog/Digital Display

An anidigi or dual display watch displays both an analog and digital time option to the wearer by providing hour and minute hands in addition to a liquid crystal window that shows the Arabic numbers. This type of watch is often utilized by military and emergency service personnel who like the duo display for job-related duties such as synchronization, performing CPR, or timing with greater ease.


Every time the balance wheel swings back and forth it causes what we refer to as a beat or a tick. The maximum angle that the balance can swing from its position of rest is the amplitude. When the balance wheel is in a horizontal position on your wrist the amplitude will typically be between 275 and 315 degrees before spinning around the opposite direction another 275 to 315 degrees. Poor amplitude will affect the time your watch keeps which is why it’s important to measure the amplitude and properly maintain your watch.

Analog or Analogue Watch:

An analog watch showcases the current time utilizing hour and minute hands rather than a liquid crystal display that digitally forms Arabic numbers.

Jack has an entire collection of vintage watches with different looks that suits his outfits really well.
Jack enjoys wearing mostly vintage analog watches wherever possible.

As the clock ticks, the hands move clockwise around the dial indicating the time of day. As they progress, they reset after 12 hours and begin again to indicate a difference in AM and PM.

Annual Calendar:

The annual calendar is a complication that shows at minimum, the day, date, and month, often accompanied by the year. Some watches contain a perpetual or moon phase calendar as well. While the watch may account for longer and shorter months, typically it does not take into consideration leap years and therefore must be reset accordingly. Some calendar watches also require a reset each year between the end of February and the beginning of March.


Along with many other factors, magnetization can cause a disruption in time due to its interference with certain parts of the movement. Simple household items such as a television, stereo system, car, or refrigerator can cause enough magnetism to counteract the balance and prevent accurate timekeeping. By using alloy parts for certain components such as the escape and balance wheel, the watch can counteract the magnetic field without a change in time. Most mechanical and automatic watches are now anti-magnetic whereas a quartz watch is not susceptible to magnet fields at all.


The aperture is a small window that’s carved or cut into the dial to display various indications such as the day or date.

Arabic Numerals:

Arabic numerals refer to any numbers on the watch face written as such: 1, 2, 3, 4, 5, 6, 7, 8, 9, 0


The arbor is an axle that any moving part of the watch can rotate on. Think of a merry-go-round with the post in the middle of the gear that turns. That post is the arbor.


The assembly is exactly as it sounds. It’s the manufacturing process of putting all of the parts of a watch together. One of the reasons I adore luxury and vintage watches is that the assembly was generally done by hand and expertly manufactured by a quality craftsman. Today, aside from the luxury market, and even sometimes including it, most watches are assembled by machines and then inspected by hand.


The atmosphere is what indicates the water resistance of a watch by measuring the normal air pressure at sea level.

Atomic Calendar:

The atomic calendar is a complication that takes into account various lengths in months as well as leap years. Some of these can be pre-programmed thirty or forty years into the future.

Atomic Clock:

The atomic clock is the most accurate timekeeping device in the world only losing approximately one second in every 1,400,000 years. Broadcasted via a radio signal in Boulder, Colorado it’s powered by the US National Institute of Standards and Technology. Utilizing the vibrations of atoms in a metal isotope similar to mercury, an atomic clock relies on this radio transmission only requiring the user to set the timezone.

Auto Switch Backlight:

If activated, a watch’s backlight will automatically illuminate the dial when you turn your wrist toward your face.

Auto Repeat Countdown Timer

An auto-repeat countdown timer automatically resets itself and starts timing again until a stop button is pushed.

Automatic Watch:

Invented by Breguet in the 18th century and first worn by John Harwood, an automatic movement is similar to a mechanical watch, but is wound by the daily movements of the wearer’s wrist. Rather than having to manually wind the stem of the watch, a tiny rotor moves in unison with your wrist which ratchets the mainspring one tick at a time.

A watch that is wound by the everyday movements of the wearer. A tiny rotor turns and swings whenever the watch is moved. This in turn rotates a tiny gear that ratchets the larger mainspring gear one click at a time. Often having a reserve, the wearer can go a couple of days without having to reset the watch by winding the stem. However, after about 36 hours, the watch if left unworn will have to be manually wound to restart its process.

Auxiliary Dial:

An auxiliary dial is just an extra dial on the face that can be used for a variety of indications depending on the complication.

The “B” of Watch Parts, Pieces and Functions

Balance Cock:

A small bridge that secures the balance wheel with the movement.

Balance Spring:

The balance spring, often called a hairspring due to how fine it is, is a very thin spring, no thicker than a strand of hair that coils and recoils causing the balance wheel to swing back and forth regulating the accuracy of time.

Balance Staff:

Another word for the Arbor.

Balance Wheel:

An integral part of any mechanical watch, the balance wheel oscillates to divide and regulate time equally the same as a pendulum does in a clock.


A band is a metal bracelet that snugly wraps around your wrist keeping the watch in position.

A Collection of Rolex Watches with Different Types of Bracelets
A Collection of Rolex Watches with Different Types of Bracelets

Band Width:

The band width is the measurement of the distance between the lugs of the case. This is important to note when purchasing a new or replacement band or strap as it determines the size you’ll require for it to properly fit your wristwatch.

Battery Reserve Indicator:

The end-of-life function is an indicator that warns you of a soon-to-expire battery in a quartz watch. This indicator is seen when the wearer notices the second hand jumping in two to four-second intervals which will indicate the battery is about to go into failure within approximately two weeks.

Batteryless Quartz Watch:

A recent hybrid technology, the watch runs without winding or a battery. Typically using a small electronic generator, the watch stores energy in its own rechargeable battery device which causes the watch to keep time. Typically, these watches are known under proprietary brand names and must be worn regularly similar to that of an automatic watch.


The barrel is a thin drum that encases the mainspring in a mechanical watch and uses a tooth-like rum to drive the train. What’s important to note is that its size is a direct reflection of how long the power reserve will hold out in a watch. If a power reserve is of utmost importance to you, consider trying to find a double barrel that significantly increases the reserve. Some watches feature a Double-Barrel which allows for extra long power reserve. The toothed rim of the barrel drives the train.


One of the better-known watch parts, the bezel is the ring found surrounding the dial of your watch. Often made of precious metals, various types of bezels can be used to measure speed or distance, as well as keep track of elapsed time.

Seiko Divers watch
A Seiko Diver’s Watch with a Distinct Bezel

Bi-Directional Rotating Bezel:

This is a bezel that can be rotated both clockwise and counterclockwise. To keep track of elapsed time, you will require this type of bezel.

Box Hinge Case:

A box hinge case is a very heavy case with reinforced hinges and heavy metalwork supporting to support the bow/pendant.


The very top of the neck of a pocket watch is located above the crown. This is where the fob or chain is attached.


Similar to the band, the bracelet is a metal strap that secures the watch to the wrist using links that can be removed for sizing.

Breguet Spring:

In 1795 Breguet realized that the spiral hairspring tended to bunch as it coiled and recoiled. That change in gravity disturbed the balance rate so Breguet raised the last coil of the spring and gave it a smaller curve which greatly improved the rate and also minimized wear on the balance pivots.


The bridge of a watch is a metal plate that contains the “jewels” affixed to the main plate which forms the frame of the movement and holds the rotating gears. It’s similar to the pillars that hold up two floors of a building.

The “C” of Watch Parts, Pieces and Functions


Completely decorative with no useful purpose, the cabochon is a smooth round or oval gemstone often found set in the crown of a watch.


The calendar is a complication that shows the date and often the day and year as well.

Cambered Crystal:

Cambered crystal means that the window or glass of the watch has been arched creating almost a dome-like appearance.

Caliber (or Calibre):

Many people often wonder what the difference between the caliber and movement is. To summarize, basically, the caliber is a part of the movement that identifies the position and size of the wheel train and barrel among other components. When someone asks about the type of caliber, typically they want to know details about the movement, its origins, and its manufacturer. Most calibers are comprised of letters and numbers to identify them.


The case of the watch is the metal, or sometimes plastic or ceramic housing that contains all of the various parts of the watch. Often called the body, it’s the same as the skin of our body which holds everything in place. Often the case of a watch can greatly increase the value of the timepiece if it’s made using gold, silver, platinum, or rhodium.

Case Diameter:

The diameter of a case is the measurement from one end of the case to the other not including the crown or buttons.

Case Thickness:

The thickness is the measurement from the top of the crystal to the base of the case.


One of the most popular types of watches, for reasons I often don’t understand, a chronograph is nothing more than w watch with a stopwatch function. Able to accurately measure elapsed time while showing conventional time it’s driven by the movement and operated by two buttons, one which stops and resets the stopwatch, and the other which starts it.

The Omega Speedmaster professional
The Omega Speedmaster Professional is a famous chronograph watch

While there are various types of chronographs on the market, most people spend the extra money on the ‘name’ without ever using the feature. For more details, take a look at our Chronograph Guide.

Chronograph Rattrapante:

A rattrapante is a fly-back hand chronograph that allows the wearer to measure split-seconds or multiple events of varying durations.


The chronometer is a precision timepiece with an expertly-crafted movement that has been rated by the official Swiss testing laboratory called the Controle Officiel Suisse des Chronometers (COSC). The COSC test measures the performance of the watch at three various temperatures and five different positions for a minimum of fifteen consecutive days. Provided that the mechanical watch is accurate to -4/+6 seconds or the quartz watch is accurate to +/-0.2 seconds per day, they will be awarded the coveted COSC chronometer certificate. It’s important to note that very few watchmakers undertake the time or expense of certifying their quartz watches simply because electronic movements are innately accurate and both position and temperature don’t affect them. In fact, to the best of my knowledge, Breitling is the only Swiss watchmaker to consistently certify their quartz timepieces.


A complication or complicated watch is simply put, a watch that tells more than just the time. Simple complications include chronographs, alarms, and calendars whereas a more intricate complication, often called a grand complication can include perpetual calendars, tour billions, minute repeaters, and more.

Want to learn more about Watch Complications?


The COSC is the Controle Officiel Suisse des Chronometre which is the only official chronometer testing organization in Switzerland.


Invented by Rolex, the Cosmograph is similar to the chronograph with one exception. The tachymeter is located directly on the bezel as opposed to the outer rim of the dial which gives a more modern look to the timepiece.

Countdown Timer:

This feature is exactly what it sounds like. The function allows the wearer to determine how much of a preset time has elapsed.


The crown is the knob on the outside of the casing which is used for setting the watch and a variety of its functions. In addition to setting the watch, the crown is used to wind the mainspring. There are various types of crowns but they all serve the same basic purpose.


The crystal is the window into the watch. It’s the clear cover on the watch that protects the dial and its parts from dust, debris, and other external elements. Often made of glass, acrylic, mineral, or sapphire, each type of crystal has its benefits and drawbacks. Acrylic crystal is an inexpensive plastic that can buff to remove small scratches. Mineral crystal is more scratch-resistant as it’s heat-treated to create a uniquely hard casing. However, sapphire is the most expensive and durable crystal, Three times stronger than mineral and up to twenty times harder than acrylic, it’s by and far my favorite type of crystal on a watch.

Crystal Skeleton Caseback:

A skeleton caseback is when the back of the watch has a window made of clear crystal that showcases the craftsmanship and design of the working movement.


The cuvette is a dust cover that is sometimes present on the case of the watch.


The cyclops is a small magnified lens in the crystal that is added to enhance the visibility of the date.

The “D” of Watch Parts, Pieces and Functions

Daily Alarm:

An alarm that is activated once per day at a preset time.

Day/Date Function:

A complication on the dial of the watch that shows both the day of the week and the date of the month.

Day/Night Indicator:

See AM/PM Indicator. This feature can be found mostly in watches with a dual time display or a world time Display to help determine the time of day in other countries.

Deployment Buckle:

A deployment buckle, also commonly referred to as a foldover, is a tri-folding clasp that secures the two ends of the bracelet while permitting enough space to slide the watch onto your wrist when opened.

Depth Alarm:

Diving watches will often contain a depth alarm that sounds or vibrates when the diver passes a preset depth level. Due to minimal sight, most watches will automatically cease to alarm once the diver has moved back into position.

Depth Sensor/Depth Meter:

Another feature found on diving watches, this sensor monitors the divers depth level using water pressure. It will showcase the reading on a scale or digitally depending on the watch.


The face of the watch showing the time using various markers and indicators.


First developed in the 1970s, digital watches forgo the standard hands for easy-to-see Arabic digits that appear in a liquid crystal display. Most often found in children’s watches, sports watches, and computer watches, they are set and operated using a variety of buttons located on the side of the case.


The process of etching or carving decorative markings directly on the watch movement.

Diver’s Watch:

Specifically made for diving and water resistant to a minimum of 200 meters, a good diver’s watch will feature complications including a rotating bezel, screw-down crown, and a case back.

Dual Time:

Dual-time watches are an exceptional find for the traveling executive or someone operating in multiple time zones. The dual time is a watch that measures both local time as well as at least one other time zone. Showcased via a twin dial, extra hand, or sub-dial, these watches are sometimes referred to as world time capable.

Dual Time Zone Bezel:

A dual time zone bezel is a rotating bezel that can be used to display another time zone separate from the dial.

The “E” of Watch Parts, Pieces and Functions


An ebauche is a type of watch movement that is built to be assembled into a watch casing elsewhere. Often watch companies outside of Switzerland will utilize Swiss movements that are shipped and then assembled in factories elsewhere in the world. Many times each part of the watch is made separately to save money. Consumers should be very wary of purchasing an ebauche timepiece and should take the time to investigate the watch before making a purchase.

Elapsed Time Rotating Bezel:

An elapsed bezel is a graduated rotating bezel that can keep track of periods of time. The bezel is rotated to align the zero marker with the watch’s minutes or seconds hand. The elapsed time can then be read off the bezel, rather than the wearer having to subtract time.

Electronic watch:

Also called a quartz watch, it contains a battery-powered or energy-generated movement, which utilizes an electric current to activate a quartz oscillator to vibrate at 32,768Hz per second. These vibrations are then processed with a circuit that transforms the current into an impulse which feeds a stepping motor and drives the gear train. Some quartz watches have solar cells which transform natural and artificial light into energy.


An elinvar is a hairspring that’s made from a mix of metals that are specifically designed to be resistant to changes in temperature and more accurate in varying elements.

End Shake:

An end shake is when a jewel hole is worn out causing an arbor to shake.

Engine Turned:

An engine-turned watch is the process of using antique machinery to engrave delicate patterns on metal parts of the watch including dials, cases, bezels, and the actual movement. Today, this process is often referred to as “Guilloche”.

Equation Of Time:

An Equation Of Time or EOT is a complication that shows the difference between true solar time in nature and mean solar time in man. As the earth revolves around the sun in an elliptical shape and the axis is tilted – there are only 4 days a year when the day is exactly 24 hours long – April 15th, June 14th, September 1st, and December 24th. On every other day of the year, the days are slightly shorter or longer, depending on the position of the earth. The EOT complication showcases the difference between the “mean” and “true” time.


One of the most important parts of any watch, the escapement provides impulses that maintain the oscillation of the balance wheel ensuring the rate that the escapement will allow the hands to revolve.

Exhibition Caseback:

The same as a skeletal case back, the purpose is to showcase the movement through a crystal located on the back of the case.

The “F” of Watch Parts, Pieces and Functions


Another word for the dial.

Fly-back Chronograph:

A fly-back is a chronograph that restarts automatically the moment it is brought back to zero. Exceptionally useful to aviators, it allows the pilot to continue usage without having to stop, reset, and start the chronograph over again.

Flyback Hand:

The flyback hand is a second hand on a chronograph that is used to time several events of varying times. It was given the name “fly back” due to how quickly it jumps back to the zero marker when reset.


A fob is nothing more than a watch chain often present on pocket watches.

Preston wearing a pocket watch with an albert double chain


The fork is part of the pallet fork and arbor which looks very similar to a pitch fork and is used to engage the roller jewel on the balance.


Also referred to as complications, functions are the various tools and tasks able to be used on the watch.

The “G” of Watch Parts, Pieces and Functions

Gear Train:

The gear train is a system of gears that transfers power from the mainspring to the escapement.

GMT Time Zone:

GMT or Greenwich Mean Time is also known as UTC (Universal Time Coordinated) or Zulu Time. It is the international standard that all world time is set to as originally governed at the International Meridian Conference in 1884.

Raphael in cufflink matching his Rolex
Raphael in cufflinks matching his Rolex GMT

Every time zone in the world is referenced against GMT and is unaffected by daylight savings time. When you hear of GMT being referenced in horology, it refers to the ability of the watch to show dual time zones one of which will be in a 24-hour mode. This allows the wearer to know if that time zone is currently in AM or PM.

Gold Filled:

Gold filled is a layer of gold bonded to another metal. While not the same as solid gold, gold-filled watches contain roughly 100% more gold in them compared to gold plating making them more valuable and tarnish-resistant.

Gold Jewel Setting:

In some luxury watches, the craftsman will mount the jewels in a solid gold setting.

Gold Plated:

Gold plating, also known as gilt, is a thin layer of gold that is fused onto another metal to make it appear as if it were gold. Unfortunately, gold plating tarnishes rather quickly and can develop what looks like green skin. Its thickness is measured in microns, but regardless of how thick the plating is, I strongly advise against purchasing a gold-plated watch. It may look resplendent for a few months but it will quickly deteriorate making it look cheap and tacky.


Guilloche, previously talked about as Engine Turning is an engraving process where fine, intricate patterns are etched into the metal parts of the watch.

The “H” of Watch Parts, Pieces and Functions


The hairspring is a very fine spring no thicker than a strand of hair in a mechanical watch that causes the recoil of the balance wheel. Also known as the balance spring, it regulates the time based on its length and adjustment.


The hallmark is a stamp or engraving to indicate the origin and quality of metal such as gold.

Helium Escape Valve:

Diving watches used by professionals are designed for deep-sea expeditions. Due to the water pressure experienced at such deep levels, helium will begin to push its way into the body of the watch. Without the escape valve, the helium could build up and cause the crystal to pop out. Divers use this valve to bleed the helium as they decompress to avoid the watch being damaged.

Hand Winding:

A hand-winding watch is the same as a manual or mechanical timepiece. It requires the wearer to wind the watch regularly for it to keep accurate time.

There are many factors that you need to take into account when buying a vintage watch.
This vintage Services watch is wound by hand to keep it ticking.

Winding the crown, causes the mainspring to wind up and release energy which powers the watch.


You’ll often hear me refer to the term horology which means the study and science of time. In addition, it also encompasses the art and craftsmanship of watchmaking.

Hourly Time Signal:

If activated, the hourly time signal will chime every hour on the hour.

Hunter/Hunting Case:

The hunting case is a pocket watch case that completely covers the watch.

Hunting Time:

For many years, hunters and fishermen have used the phases of the moon to determine the time to hunt or fish. These watches show the moon’s age as well as what time the sun will rise and set based on location.

The “I” of Watch Parts, Pieces and Functions


The incabloc is a shock absorber that protects the balance staff from breaking if the watch is dropped or impacted.

Index Hour Marker:

The index hour marker is a line or indicator on the dial of an analog watch that is often used instead of numerals.

Integrated Bracelet:

An integrated bracelet is a band that is a direct reflection and is built directly into the design of the case of the watch.

The Audemars Piguet silver-toned Royal Oak watch (left) and the Maurice Lacroix stainless steel Aikon watch (right) [Image Credit: L – Audemars Piguet; R – Maurice Lacroix]
The Audemars Piguet silver-toned Royal Oak watch (left) and the Maurice Lacroix stainless steel Aikon watch (right). Both watches feature integrated bracelets. [Image Credit: L – Audemars Piguet; R – Maurice Lacroix]


Refers to a mechanical watch that will run at the same rate regardless of whether it is fully wound or not.

Ionic Plating:

Ionic plating is a process that allows a darker grey-to-black compound to be applied to stainless steel watch cases and bracelets giving the watch a modern look over the standard appearance of metal.

The “J” of Watch Parts, Pieces and Functions


A jewel is a real ruby or synthetic gemstone that acts as a bearing for the gear trains to reduce friction which can adversely affect the accuracy of timekeeping.

Jump Hour/Minutes:

A jump display uses numbers displayed in the aperture rather than a hand continuously moving. While the motion of a hand moving is far more common, time can just as easily be indicated using the aperture as a jumping display to show the hour or even the minutes.

The “K” of Watch Parts, Pieces and Functions


As with all jewelry, a karat is an indicator that shows the purity of a metal such as gold. Because metals such as gold are too pliable to use in watches, they’re made into an alloy to increase their strength. The ratings are an expression of the proportion of pure metal to other metals. Using the karat scale of 1/24, 24k gold is pure, whereas 18k gold is 18 parts of pure metal to 6 parts of other metal.

Key Set:

A key set is a term used for a watch that is set using a small key, rather than winding the crown. While not as common anymore, most antique pocket watches are where you would find a key set movement.

The “L” of Watch Parts, Pieces and Functions

Lap Memory:

Many quartz watches have a built-in lap memory which can store the history of lap times in a race for viewing later.

Lap Timer:

The lap timer is a chronograph function that breaks up the time segments or laps of a race. At the end of a lap, the timer resets to zero so it can time the next lap of the race.

Lever Escapement:

A lever escapement is part of the movement that divides into two pallets that lock and unlock the escape wheel teeth. This process is managed by the balance wheel which engages the opposite end of the lever causing the escape teeth to move on the pallets and lift the lever so it can impulse the balance.

Lever Set:

Most commonly found on the railroad, a lever-set watch required the conductor to remove the crystal and pull a small lever to set the time. This was used as a safety measure to avoid train collisions.

Liquid Crystal Display:

Liquid crystal displays or LCD watches are another term for digital watches and show a numeric Arabic display by using a liquid that’s encased between two clear plates.

The stopwatch function of a Casio chronograph alarm watch.
The stopwatch function of a Casio chronograph alarm watch.

Activated by electronic impulses, the numbers are made up of seven lines that all form the number eight when fully lit.


Luminous markers and hands are made by applying a glow-in-the-dark coating to the respective indicator allowing them to illuminate automatically in a darker environment.


The lugs are the part of the watch case that the bracelet, strap, or band attaches to.

The “M” of Watch Parts, Pieces and Functions

Magnified Window:

Another term for a Cyclops.

Main Plate:

Also called a base plate, this is the primary piece of metal that all of the other parts of the movement are mounted on.


The mainspring is a coiled spring that gives power to drive the gear train of the watch.

Manual Wind Movement:

Manual wind movement is another word for mechanical movement meaning that the wearer must manually wind the crown for the watch to work. Typically once the watch is fully wound it will keep time for 35-45 hours before needing to be rewound.

Measurement Conversion:

Typically, this is a graduated scale found on the bezel or dial that allows the wearer to convert one type of measurement into another.

Mechanical Movement:

As you know by now, a mechanical watch is typically the favoured type of movement among watch enthusiasts. This term refers to a watch that runs without any electrical source.

Spring drive watch technology
Spring drive watch technology

Micrometric Regulator:

The micrometric regulator is a timekeeping regulator used in high-grade watches that can be finely tuned by the adjustment of a small screw.


A micron is used to measure the thickness of gold plating. One micron is a thousandth of a millimeter.

Military Time:

Military time is more commonly referred to as the 24-hour clock. To convert 12-hour time to 24-hour time, simply add 12 to any p.m. time. To convert 24-hour time to 12-hour time, simply subtract 12 from 13 to 24.

Mineral Crystal:

Essentially just a form of synthetic glass, mineral crystal is more scratch-resistant than plastic but when scratched is virtually impossible to polish.

Minute Repeater:

A minute repeater is a complication that strikes hours, quarters, and minutes using a gong. A notably complicated achievement, minute repeaters can increase the value of a watch exponentially and utilize a slide or button on the case to activate.

Moh’s Scale:

Invented by Austrian mineralogist, Friedrich Moh, the scale is a way of measuring a mineral’s hardness and resistance to scratching. The scale ranges from talc, the softest, to diamonds, the hardest (talc = 1, gypsum = 2, calcite = 3, fluorite = 4, apatite = 5, feldspar = 6, quartz = 7, topaz = 8, corundum = 9, diamonds = 10). The vast majority of gemstones have a rating of 6 to 8. It should also be noted that sapphire crystals have a rating of 9, and mineral crystals have a rating of 6.

Mono Pusher Chronograph:

A mono-pusher is a type of chronograph that is operated using a single button rather than two or more.

Moon Phase:

A particular favorite complications among horologists, the moon phase is a window that showcases the various phases of the moon.

The moonphase view on a JLC watch up close
The moonphase view on a JLC watch up close

Mother of Pearl:

Mother of pearl is the creamy white, blue, or pink gleaming interior of a freshwater mollusk that is commonly used for dial decoration.


The movement can easily be defined as the engine or motor of a watch. There are three main types of movements; mechanical, automatic, and quartz.

The “N” of Watch Parts, Pieces and Functions


Both Roman and Arabic numbers are used in watchmaking.

The “O” of Watch Parts, Pieces and Functions

Oil Sink:

An oil sink is a recessed pool that circles a pivot and holds a small amount of oil to lubricate the gears.

The “P” of Watch Parts, Pieces and Functions

Pair Case Watch:

A pair case watch is a pocket watch that is encased in a second protective case in addition to its own.


A pedometer is a complication that counts the number of steps taken by the wearer.


The pendant is the neck of the pocket watch where the crown and bow are located.

Perpetual Calendar

A perpetual calendar is a complication that is capable of showing at least the day, date, and month. Many also display both the moon’s phase and year. The perpetual calendar takes into account short and long months as well as the leap year.

Physical Vapour Deposition:

PVD is a coating of titanium nitrate that is applied to the watch and then covered by a coating of gold to obtain a gold-colored finish to the watch.


The watch plate is the back and front of the case that gives access to the internal parts.


This term references the various tests performed on a watch to ensure its accuracy when held in different positions.


Another word for platinum.


One of the rarest and most durable metals, platinum doesn’t tarnish and consistently stays as radiant as it was new. It’s one of the most common choices for limited-edition pieces.

Power Reserve Indicator:

A power reserve indicator allows the wearer to see the amount of time before the watch will need to be wound.

The Maurice Lacroix Reserve de Marche watch as worn by Nathan
The Maurice Lacroix Reserve de Marche watch as worn by Nathan


Is a scale on a chronograph that can measure pulse rates.


A push-piece is just another name for a button on the side of the case.

The “Q” of Watch Parts, Pieces and Functions

Quartz Movement:

Quartz watches are another name for electronic watches that utilize a battery or capacitor to charge and run the watch. While they’re not nearly as revered as mechanical watches, they are far more accurate than even the most expensive manually wound watches.

The “R” of Watch Parts, Pieces and Functions


A regulator separates the minute and hour hands onto different axial and sub-dials. This allows the wearer to quickly tell time without having to worry about the hands covering each other.

Reserve de Marche:

Another word for Power Reserve Indicator.


A retrograde watch sets out the time in a linear format rather than the circular dial we’re used to. Instead of the hands moving in a circle, they move in an arc and then jump back to the beginning.

Roman Numerals

These are the numbers that will most likely to appear on watch dials in the format: I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII

Rotating Bezel:

A rotating bezel is a bezel capable of being turned clockwise, counterclockwise, or both.


This is the oscillating part of an automatic watch that winds the mainspring, preventing it from having to be wound manually. It looks like a flat piece of metal that swivels on a pivot with the motion of the wearer’s arm.

The “S” of Watch Parts, Pieces and Functions

Sapphire Crystal:

Sapphire crystal is an exceptionally hard transparent material that is chemically the same as natural sapphire and ruby, but without the other elements like iron and titanium that give the gem its color. Commonly used for high-end watch crystals it’s synthetically made by crystallizing aluminum oxide at very high temperatures until it measures 9 on the Mohs scale.

Screw Down Crown:

A screw-down crown is a crown that is throated and can tighten when the wearer screws it in. It utilizes a gasket that compresses and seals the opening which ensures its resistance to water. This is a required feature for any watch you intend on getting wet.

Second Time Zone Indicator:

This indicator is an additional dial that can be used to set a separate time zone allowing the wearer to view two time zones at once.

Shock Absorber:

The shock absorber is a bearing that captures the shocks taken by the balance staff and protects its pivots from being damaged.

Shock Resistant:

This is defined as the watch’s ability to withstand an impact equal to that of being dropped onto a wood floor from a height of 3 feet.

Casio G-Shock Close up
Casio G-Shock


A cheap metal compound that resembles actual silver.

Skeleton Watch:

A skeleton watch is a case with no dial that has a transparent front that allows the wearer and admirers to view the movement without having the take the watch off.

Slide Rule:

This is in essence a navigation computer that consists of a scale on the outer edge of a watch face allowing the wearer to perform mathematical calculations such as fuel consumption or converting miles into nautical miles or kilometers.

Solar Powered Batteries:

Just as they sound, these batteries are found in a quartz watch and are recharged using solar panels found on the dial.

Split Seconds Chronograph:

This is a more complicated chronograph consisting of two center seconds hands. The additional hand can be stopped independently while running at the same time as the main hand. It can also be made to catch up with the running chronograph which is why it’s called a “split-second hand”.

Spring Bar (or pins):

These are spring-loaded pins located between the lugs and used to attach the bracelet, band,, or strap to the case.

Stainless Steel:

A very durable metal that is rust and corrosion-resistant. I almost always recommend this material to someone who can’t afford a precious metal such as solid gold or platinum.


Another word for a chronograph.

Stepping Motor:

This is a part of the analog movement in a quartz watch. It moves the gear train which turns the hands on the dial.

Sterling Silver:

At 92.5% pure, Sterling silver is a very glossy precious metal often found in watches and on their dials.


Similar to the bracelet or band, the watch strap is usually made of leather, rubber,, or a fabric such as nylon. It serves the same purpose as both the bracelet and band.

Subsidiary Dial:

The subsidiary or sub-dial is an auxiliary dial used for various purposes and functions.

A subdial date on a Patek Philippe watch
A subdial date on a Patek Philippe watch

Swiss Made:

The marking of a truly exceptional watch, a timepiece bearing the Swiss Made label indicates that the entire movement was manufactured, cased,, and inspected by the manufacturer in Switzerland. In addition, at least 50% of all of the watch components must be made, assembled,, and inspected in Switzerland. The laws surrounding this are very strict to eliminate replica Swiss watches and to ensure a standard of regularity for the consumer.

Swiss Movement:

Swiss Mov’t as commonly stamped on watches should not be construed as being Swiss-Made. To label a watch as Swiss Mov’t, only the movement must be made in Switzerland, where the remainder of the watch, its casing,, and its components can be manufactured, assembled, and inspected anywhere else in the world.

Swiss A.O.S.C.:

A mark or origin, this label denotes that the watch was assembled in Switzerland and that the components are Swiss-made as well.

The “T” of Watch Parts, Pieces and Functions

Tachymeter Scale:

A notably common feature in chronographs, the tachymeter measures speed over a specified distance. The wearer will start the chronograph at the starting line and stop it upon finishing.

Tang Buckle:

A tang buckle is the most common strap found in today’s market. A traditional loop and pin, it resembles a belt buckle.

Tank Watch:

The tank watch was designed by Cartier and is a rectangular gentleman’s style watch with bars running its sides resembling the tracks of a tank.

The Cartier Tank is wearable and allows you to wear it with everything.
The Cartier Tank is versatile and allows you to wear it with everything.


A function that allows the wearer to register intervals of time without having to worry about the time of day.


Resistant to saltwater corrosion, titanium is increasingly being seen in diving watches and is both stronger and lighter than stainless steel.


A tonneau watch is a barrel-shaped case with two bulging sides.


The totalizer (or totaliser) is a mechanism that tracks elapsed time. It’s usually called a sub-dial.


The Tourbillon is a horological wonder and works in harmony to compensate for a change in position. By mounting the balance wheel and escapement in a rotating cage, the balance and escapement can rotate completely to avoid errors caused by a change in the position of the wearer’s wrist.

A close-up of the tourbillon in an Audemars Piguet watch [Image Credit: Audemars Piguet]
A close-up of the tourbillon in an Audemars Piguet watch [Image Credit: Audemars Piguet]

Tourbillons typically rotate once every minute but some manufacturers provide a four or six-minute tourbillon as well. This is an extremely difficult complication and therefore will drastically increase the cost and value of a watch.

The “U” of Watch Parts, Pieces and Functions

Uni-Directional Rotating Bezel:

Typically found on diving watches, this bezel can rotate in only one direction rather than both. The reason divers like this is due to the fact that it prevents them from running out of air by overestimating any remaining supply should the bezel accidentally be rotated in the wrong direction.

The “V” of Watch Parts, Pieces and Functions

Vibration Per Hour:

The VPH is the movement of an oscillating part that is limited to two extreme positions.

The “W” of Watch Parts, Pieces and Functions

Watch Winder:

A watch winder is a machine that automatically winds your watches when not in use.

Water Resistance:

Watches marked as water-resistant can withstand the effects of water to a limited extent. It’s very important to check the manual and warranty to ensure you don’t overestimate its resilience. It’s also important to remember that as a watch ages its water resistance is decreased so it’s best to check it once or twice a year.


This is a method of winding the crown which tightens the mainspring of the watch causing the watch to keep time.

Winding Stem:

Another word for the crown.

World Time Complication:

An intricate complication that tells the time of up to 24 different time zones. These watches are often called World Timers.


This is an illegal term used in the industry and should be a red flag when purchasing a timepiece. If you see a watch labeled as such or a salesman tells you that it is, just run.

The “Y” of Watch Parts, Pieces and Functions

Yacht Timer:

Used to sound warning signals during the countdown of a race.

How many of these terms did you know? Were there any that you found particularly helpful? Let us know in the comments!