Watch Glossary

Acrylic Glass -

A synthetic material easily altered at higher temperatures. This glass is resistant to both corrosion and the elements. Scratches to the acrylic glass can be polished out easily.

Alarm -

An alarm allows users to have a signal sound at a predetermined time.

Annual Calendar -

A feature allowing users to set the date one time a year. The end of February is usually the time of year this function needs to be performed.

Automatic -

This term refers to a watch caliber that is automatically wound. The winding of the mainspring is generally done by the arm or wrist of the wearer. In order to protect the watch from too much tension, a slipping clutch is used. The main rotor in the watch is also very widespread to avoid damage.

Balance spring -

These springs are used in mechanical timepieces. The spring is attached to the balance wheel of the watch and can be used to adjust the rate of the piece.

Balance Wheel -

This part of a mechanical watch regulates the beat through a series of vibrations. The balance wheel features a rim and the hairpin. In grandfather clocks, the balance wheel is featured as the second hand. Modern balance wheels are capable of between 21,600 to 28,800 beats per hour. Without an accurate and functional balance wheel, a watch will not be able to run precisely.

Bezel -

The ring that surrounds the glass on a watch is referred to as a bezel. The bezel can come in a fixed or moveable design. Many of the diving watches on the market feature a multi-directional bezel that can be used to keep track of the time a diver has been underwater. A bezel is generally made of ceramic or metal.

Bicompax -

The amount of subdials on a chronograph is referred to as a Biocompax. Generally, the Biocompax can be found at the 3 o’clock and 9 o’clock position on a chronograph. Some chronographs feature a Triocompax with three points that form a V.

Breguet Balance Spring -

This type of balance spring helps to reduce the amount of curvature on a timepiece due to the raised coil it has. Abraham-Louis Breguet invented this part in 1795. The Breguet balance spring, or Breguet hairspring as it is sometimes called helps a watch run in a more precise manner.

Caliber -

The movement of a watch is also referred to as the caliber. When writing out the caliber of a watch, manufactures usually place the name of the timepiece at the beginning.

Case -

A case houses the internal parts of a watch. They are generally made from metal like gold, silver or titanium. Lower priced watches will usually feature a gold or silver plated case.

Caseback -

The caseback is the backside of a watch. On some watches, the caseback will be transparent to allow the owner to watch the inner workings of their timepiece. Usually, manufacturers will put their name or logo on the caseback along with other details.

Chiming Mechanism -

Most mechanical watches use a separate apparatus to house the chiming mechanism. This mechanism features a hammer which hits things like a gong or even a set of chimes to alert users of the time.

Chronograph -

This is a stopwatch that can be used in sporting events.

Chronometer -

These devices are known for how precise they are. These calibers are certified for their preciseness by the Official Swiss Chronometer Testing Institute.

Co-axial Escapement -

The co-axial escapement was invented in the 70s to be used as an alternative to the Swiss lever escapement. The name for this apparatus was given because of the dual wheels mounted on parallel shafts. The use of the escapements became very popular once watchmakers saw the lack of friction produced. By using this escapement, watchmakers were able to use less lubricant while allowing the watches to run for longer periods of time.

Complication -

An additional function offered on a watch is known as a complication. Things like calendars, alarms and moon phase settings are very common complications. The more complications featured on a watch, the harder it is for watchmakers to build them.

Crown -

The crown is the button located on the outside of a watch’s case. This button can be used to change the settings for date and time. On most mechanical timepieces, the crown can be used to wind up the mainspring.

Crystal -

The crystal is what covers the face of a watch. This cover can be made from plastic, crystal and even synthetic materials.

Deployment Buckle -

The deployment buckle has hinges and snaps to make it easy for the user to take on and off their watch. These types of bands are usually more expensive, but are much more comfortable on the wrist.

Diving Watch -

Recreational and professional divers make good use of a diving watch. Standards like ISO 6425 and DIN 8306 are generally applied when making these watches. Many of the higher quality watches made for divers can be submerged in up to 200 meters of water without breaking. These types of watches generally feature illuminated hands and numbers to make it easy for divers to see while underwater. The bezel on these watches also feature markers to indicate how many minutes a diver has been submerged. Generally, these bezels can only be rotated one way to help divers avoid making grave errors while trying to calculate the time they have been in the water.

Double Barrel -

Watch calibers with two barrels are referred to as a double barrel watch. With these two barrels, the watch will have an extended power reserve.

Dual Timer -

A dual timer watch tells the time in two different time zones. Additional time zone readings may come from sub dials or even an additional hand.

Escape Wheel -

This watch part features a pallet fork escapement. Generally, this part will be in the middle of the balance wheel and train. It is meant to create a connection between these two parts and features asymmetrical teeth.

Escapement -

A wound watch spring is able to get a steady release due to the escapement used during construction. Periodically, this part will catch the gear train and keep the watch spring unwinding at a steady pace. The escapement also helps the oscillation system by providing it with new energy to keep the process going. The overwhelming majority of watches on the market today feature the escape wheel and pallet fork escapement design. The escape wheel on the watches also doubles as the second hand. Along with the balance wheel, the pallet fork moves back and forth during operation. The pallet fork is designed to hook onto the escape wheel and release it at the right time. By doing this, it allows the wheel to move a tooth at a time.

ETA SA Swiss Watch Manufacturer -

This watch manufacturer produces pieces with Swiss movements. They are also a member of the Swatch Group of watchmakers.

Flyback Chronograph -

This type of chronograph has a very special function. After the piece begins running, the users will be able to take it back to the start with just a push of a single button. Generally, standard chronographs will require the user to press a button up to three times to restart the timer. Originally, these types of chronographs were used by aviation enthusiasts and the military. When trying to time maneuvers, military members needed a chronograph that could be reset in a hurry.

Gasket -

In order for a water resistant watch to work properly, it will need a gasket. Generally, these gaskets will be located in the case back or under the crystal of the watch. Every two years, a watch owner will need to have their gaskets checked to ensure they are working correctly and do not need to be changed.

Geneva Seal -

This type of seal is used to show a person the quality and origin of a watch. In times gone by, this seal was stamped right into the metal on the movement of a watch. Modern times have led to innovations and the seal is now embedded microscopically into a watch. Even the smallest parts of a watch can carry this seal on them. For a watch to have a Geneva Seal, the construction of the timepiece must be done in the Canton of Geneva. Other criteria like the finish of the watch and the quality it has are also taken into consideration before earning this marking. The Office for the Voluntary Inspection of Watches From Geneva are in charge of granting watchmakers access to their seal.


The meter for all time is set by GMT or Greenwich Mean Time. This time zone has since been replaced by universal coordinated time. Most GMT watches display this time zone as well as another one chosen by the user.

Guilloché Dial -

The Guilloché dials feature a special finish and engraving. The Guilloché designs are made up from a complex pattern of connected lines.

Hairspring -

A hairspring or balance spring as it is sometimes known is a vital part of a watch’s balance wheel. The oscillation system located in a mechanical watch relies heavily on this part. The hairspring expands and contracts a number of times each second. By doing this, it keeps the inside components of a watch running smoothly and also provides power to the oscillation system. This component is usually made of things like metalloid silicon or even Nivarox alloy.

Helium Escape Valve -

When submerged in water, a watch can be put under a lot of pressure. The helium escape valve is designed to protect a watch from this type of damage. This valve works to equalize the pressure that can occur when bringing a submerged watch back to the water’s surface. These valves can work automatically or manually, if needed.

Jewels -

Bearings or gears are made out of synthetic rubies or sapphires. These are usually used to reduce the amount of friction. They are also used to add additional bling and visual appeal to a timepiece. Common gemstones used in luxury watches include diamonds, rubies and sapphires of a multitude of different colors.

While these can improve and individualize the look of a timepiece, it does typically have a negative impact on the price of a watch if these are after market pieces. After market means that the changes to the watch were undergone post purchase and not by the brand itself. These alterations detract from the value of the piece as it has now been tampered with and is no longer in it’s original condition. One of the major problems with after market alterations is that luxury watch brands will refuse to accept and make fixes to the watch. For example, if you added jewels to a Patek Philippe watch and then attempted to return the watch to Rolex to repair any small damage, Patek would not accept the watch as it has been changed.

Limited Series -

This term refers to the fact that a limited number of watches have been made in a particular series.

Lugs -

Part of a watch where the band or bracelet is fastened.

Luminous Hands -

These hands are usually adorned with a material that allows them to glow in the dark. Traditionally, materials like tritium were used to make the hands of a watch luminous. Zinc compounds will react with the tritium, which is what causes the hands of a watch to glow. Most of the modern watches with this feature will use Superluminova. This material is non-radioactive and much safer to use then tritium. The pigments, known as lume, are activated by light. Once the light is taken away, these particles glow to light up the hands of the watch.

Luminous Numerals -

These numerals are coated with a material to make them glow in darker areas. Tritium was used in the past to create this luminous appearance, but newer watches use Superluminova. The pigments or lumes in this substance are charged by light and then glow when the light is removed.

Mainspring -

This part of a watch is what provides the energy needed to keep it running. The mainspring is located in the barrel of the watch and is wound up either manually or with a rotor. Watches also feature escapement to prohibit the transfer of too much energy to the gears all at once. The escapement helps to ensure the right amount of energy is transferred

Manual Winding -

With the manual winding process, the mainspring gets tensed and then releases energy to the train of the watch. Winding is done by twisting the crown on the watch.

Mineral Glass -

Lower priced watches generally use mineral glass as the crystal. This material is durable, but not nearly as scratch resistant as sapphire glass. There are processes used to harden this glass and increase the durability.

Minute Repeater -

A minute repeater is a watch feature that chimes at a certain time of day. In order to activate this complication, the user has to select the time of day they want with a few button clicks. These complications are very rare considering how hard they are to implement.

Perpetual Calendar -

This complication shows the accurate date in relation to the Gregorian calendar. This feature will be correct until 2100 and will require no alterations until then. This type of calendar compensates for shorter and longer months, as well as leap year.

Power Reserve -

Power reserves kick in after a watch is fully wound. The reserves will help to ensure the watch does not have to be rewound on a constant basis. Many newer watches have this feature.

Power Reserve Indicator -

This indicator shows the user how much time is left before their mechanical watch will be without power. When the power is about to run out, the watch user is able to rewind the watch and restore the energy needed.

Quartz Watch -

These types of watches are powered with quartz crystal. The crystal receives the power needed to operate the watch through vibrations. The vibration received is converted into an electronic pulse. The pulse then provides power to the stepping motor that moves the hands of the piece. In the 70s, these watches were very popular. During the Quartz Crisis, these watches became rare. Generally, the current provided to the quartz watch comes from a battery.

Quickset Date Feature -

Setting the date and time on a watch is easy with the quickset date feature. To set this important feature, users will have to pull out the crown. Usually, it will only take a few rotations to get the proper changes made.

Reference Number -

This number is the equivalent of the watches model number. When searching for a vintage watch, knowing the reference number can make it much easier to find.

Rotatable Bezel -

Diving or pilot watches often feature a rotatable bezel. This is a movable ring that generally surrounds the dial of the watch. On diving watches, these bezels help the diver to surmise how long they have been underwater. These bezels can usually only turn one way to reduce the room for error that exists when every minute counts. There is a 60-minute scale on the bezel that is issued by the diver to make sure they are not in the danger zone in regards to their amount of oxygen.

Rotor -

Automatic watches feature a rotor, which is a round metal piece that is used to wind and alter settings. As the rotor begins to move, the rotor will put pressure on the main spring, thereby winding the watch.

Sapphire Glass -

This type of glass is produced by synthetic alterations. This material is much harder and will resist scratches better than other materials like acrylic or glass. Usually, sapphire glass is used in the construction of higher end watches due to its durability.

Screw Down Crown -

This part of a watch screws in the case with ease. By screwing this piece in rather than pushing it in, you will be able to improve the waterproof nature of the watch. Rolex was the first manufacturer to use this type of crown starting in 1926.

Screw Down Push Pieces -

These pieces go into the case of the watch by screwing them down. By not having to push in the pins, the owner of the watch is able to reduce possible damage and increase waterproofing.

See Through Case Back -

A see-through case back is generally made from mineral or sapphire glass. Having one of these types of case backs will allow a watch owner to view what is going on inside of their piece.

Shock Protection -

Dropping a watch can create a lot of damage without the right protective measures in place. Shock protection is a system that watch manufacturers use to keep the internal parts of a watch safe from dropping. Generally, this system is comprised of a bunch of metal springs. These springs are designed to take the brunt of impact and protect parts like the balance wheel and pivots. Generally, a watch that is deemed shock proof can withstand a drop from up to one meter. Incabloc is commonly used in most shock protected watches, but there are a number of watch builders who have their own systems in place.

Skeleton Watch -

Skeleton watches are specifically made to show owners what is going on inside of their timepiece. Many of the skeleton watches on the market are considered works of art due to their intricate design.

Small Seconds -

Small seconds is a dial where seconds are displayed. Usually, this type of dial is found on pocket and manual watches. The second hand on these types of watches are attached to the minute hand. This part of a watch is also referred to as a subsidiary second hand.

Stainless Steel -

The term stainless steel is used to identify steel with a certain type of purity level. Most watchmakers use this material due to the durability it has. Stainless steel is also non-corrosive. The most common stainless steel alloys used in watch production contain nickel and chromium.

Stop Seconds -

With stop seconds, watch users are able to set their piece to an exact second. If the crown is pulled out, the second hand will cease to move. The user will be able to reset the time correctly. After the right time is set, the watch owner can put the crown back in and resume normal function.

Stopwatch -

Most watches feature stopwatch capabilities. This allows a watch owner to measure a time period in seconds. If a watch does feature a stopwatch design, it is generally called a chronograph.

Subdial -

A subdial is usually located on the face of a watch. This dial serves a number of different purposes like keeping track of the date or even elapsed minutes and hours.

Superluminova -

This material is used to make the hands on a watch glow in the dark. Over time, the luminosity produced by this substance fades. This material is non-radioactive unlike other materials used in the past such as tritium. Superluminova is also more stable and can stay luminous for years to come.

Swiss Made -

In order to be deemed Swiss Made, a watch must be assembled controlled and adjusted in Switzerland.

Tachymetric Scale -

In order to calculate units in an hour, watchmakers will use Tachymetric scales. Generally, this scale will be on the edge of the dial or the bezel of the watch. Watch owners can time themselves while driving to determine how many miles they travel in a predetermined increment of time. Watchmakers also refer to the Tachymetric scales as a tachymeter or tachometer.

Telemeter Scale -

Calculating distances on a watch is easy when using telemeter scales. Some people use these scales to determine how far away bad weather is from their location. By timing the lightning strikes around you, it will be easy to tell how far off a storm is. Generally, this scale uses the large second hand of a watch to point in the direction of what needs to be timed. Many troops also use this feature to determine how far away enemy gunfire is from their location.

Tourbillon -

The tourbillon on a watch has a round shape and is designed to turn one time every minute. The oscillation and escapement system is located within the tourbillon. These systems stay in a vertical position due to the shape of the tourbillon and with a little help from gravity. This system is now found in some of the highest quality watches on the market. Due to the complexity of the tourbillon, only experienced watchmakers can make it work correctly.

Tricompax -

A Tricompax is a term used to describe how three subdials are arranged. Usually, they are in the shape of a V.

Water Resistance -

Water resistant watches are able to withstand a small amount of moisture. Generally, a water resistant watch should not be worn when diving. Most sport watches are only submersible up to 50 meters. In order to be used for diving, a watch will have to be submersible for up to 200 meters.

Winding Mechanism -

This part is what winds a watch’s mainspring. Many older pocket watches need a key to wind the mainspring. In recent years, this design has been replaced with a crown, which is much easier to operate. Automatic timepieces use an oscillating weight and rotor when performing this function.

World Time Dial -

A world time dial is capable of telling time in up to 24 time zones. Each time zone will have a name printed in the bezel or on the dial of the watch. The scale around the watch is important because it is how the user will know what the correct time is. These types of watches are also commonly referred to as world timers.

Yacht Timer -

This timer is used during boat races. It will produce warning signals before the countdown of a race. A popular addition to many watches worn by those interested in boat races.

Year Display -

This term refers to the year that is displayed on the dial of a watch. A popular element on many watches, this particular complication appeals to many watch fanatics. Watch complications typically add value to a watch at resale, as long as they are still in good condition. Always make sure to get your watch regularly serviced (approximately every 1-3 years) to keep your expensive timepiece in good shape.