Glossary Of Watch Terms

A device that sounds a signal at a predetermined time.
A combination of one or more other metals or non-metals that often enhance its properties.
A device that determines altitude by responding to changes in barometric pressure.
Analogue Display
A display that shows the time by means of hands and a dial.
Analogue Watch
A watch with a dial, hands, and numbers or markers that present a total display of 12-hour time span. Analogue digital refers to a watch that has both a digital display and hands of a conventional watch.
A device that is not affected by magnetic fields.
Annual Calendar
Annual calendar displays the date, day of the week and month with only one manual adjustment required per year for February.
Small opening. The dials of some watches have apertures in which certain indications are given (e.g. the date and hour).
The shafts that the wheels and pinions are mounted on.
Automatic Movement
A mechanical movement that requires no winding because the rotor, part of the automatic mechanism, winds the mainspring every time you move your hand. The first automatic movement was invented in Switzerland by Abraham-Louis Perrelet in the Eighteenth century.
Auto Repeat Countdown Timer
A countdown timer that resets itself as soon as the pre-set time has elapsed and starts the countdown again. It repeats the countdown continuously until the wearer pushes the stop button.
Automatic Watch
A watch whose mainspring is wound by the movements or accelerations of the wearer's arm. On the basis of the principle of terrestrial attraction, a rotor turns and transmits its energy to the spring by means of an appropriate mechanism.
Automatic Winding
Winding that occurs through the motion of the wearer's arm rather than through turning the winding stem. It works by means of a rotor that turns in response to motion, thereby winding up the watch's mainspring. An automatic watch that is not worn for a day or two will wind down and need to be wound by hand to get it started again.
Balance Spring
A very fine spring in a mechanical watch that returns the balance wheel back to a neutral position.
Balance Wheel
The part of a mechanical watch movement that oscillates, dividing time into equal segments.
Thin cylindrical box containing the mainspring of a watch. The toothed rim of the barrel drives the train.
Largest watch show in the world. It is held every year in April in Basel, Switzerland.
Base Plate
The foundations of the movement onto which the rest of the movement is attached. The dial is mounted on the underside.
The ring, usually made of gold plate, gold or steel, that surrounds the watch face.
Bi-directional Rotating Bezel
A bezel that can be moved either clockwise or counter clockwise. These are used for mathematical calculations or for keeping track of elapsed time.
Beats per hour. Each rotation of the balance wheel, either clockwise or anti-clockwise, is one beat. The average mechanical watch oscillates at around 28,000 beats per hour.
A type of watch band made of elements that resemble links.
Complementary part fixed to the main plate to form the frame of a watch movement. The other parts are mounted inside the frame.
A hinged pin retainer used to latch one end of a strap to the other.
Decorative stone which has been carved into a round shape.
A feature that shows the day of the month, and often the day of the week and the year. There are several types of calendar watches.
A term often used by Swiss watchmakers to denote a particular model type, such as Caliber 48 meaning model 48. More commonly, the term is used to indicate the movement's shape, layout, or size.
Often used in referring to a curved or arched dial or bezel.
The metal housing of a watch's parts. Stainless steel is the most typical metal used but titanium, gold, silver, and platinum can also be used. Less expensive watches are usually made of brass and plated with gold or silver.
The underside of a watch that lies against the skin. Some casebacks are made of crystal allowing you to view the watch movement.
The middle section of a three-piece watch bracelet link.
The bell-like sound made when a clock strikes on the hour, half hour, etc.
A time that can be started and stopped to time and event.
This term refers to a precision watch that is tested in various temperatures and positions, thus meeting the accuracy standards set by an official institute in Switzerland. Most watch companies provide a certificate with your chronometer purchase.
A watch with other functions besides timekeeping. For example, a chronograph is a watch complication. Other complications coveted by watch collectors include
minute repeater, tourbillon, perpetual calendar, or split second chronograph.
Controle Officiel Suisse des Chronometres (The Official Swiss Chronometer Testing Institute) they test watches for several consecutive days, in 5 positions and at 3 temperatures. They either pass or fail the watch movement. If the watch passes it is certified as a "chronometer".
Countdown Timer
Function which measures time remaining in pre-set period of time.
Button on the outside of the case that is used to set the time and the calendar, and, in the mechanical watches, to wind the mainspring.
The transparent cover on the watch face made of glass crystal, synthetic sapphire or plastic.
Small lens on the crystal to magnify the date.
Day/Date Watch
A watch that indicates not only the date but also the day of the week.
Day/Night Indicator
A coloured or shaded band on a world time that shows which time zones are in daylight and which in darkness.
Depth Alarm
An alarm on a diver's watch that sounds when the wearer exceeds a pre-set depth. In most watches it stops sounding when the diver ascends above that depth.
The watch face. In high-end watches the numerals, indices and surface designs are applied as separate elements. In less expensive watches, they may be simply printed on the dial.
Digital watch
A watch that shows the time through digits rather than through a dial and hands display.
Double Axis Tourbillon
A mechanism that rotates the tourbillon cage and escapement through a second axis as well as through the traditional first.
Double Chronograph
A chronograph that uses two second hands simultaneously to measure split times.
Dual Timer
A watch that measures current local time as well as at least one other time zone. The additional time element may come from a twin dial, extra hand, sub dials, or other means.
Elapsed Time Rotating Bezel
A graduated rotating bezel used to keep track of periods of time. The bezel can be turned so the wearer can align the zero on the bezel with the watch's seconds or minute's hand. The wearer can then read the elapsed time off the bezel. This saves him/her having to perform the subtraction that would be necessary if he used the watch's regular dial.
Engine Turning
Decorative engraving, usually on the watch face.
Device in a mechanical movement that controls the rotation of the wheels and thus the motion of the hands.
The leading manufacturer in Switzerland for movements used in many Swiss brands.
Ring that separates the crystal from the dial.
Flyback hand
A seconds hand on the chronograph that can be used to time laps or to determine finishing times for several competitors in race.
Flying Tourbillon
A tourbillon mechanism that is supported by a cantilevered bridge (called a cock) rather than a traditional spanning bridge.
Four Year Calendar
A complication that displays the date, day, month that only requires adjustment on a leap year.
grooved pulley that equalizes the mainspring by controlling its winding or unwinding.
Most water resistant watches are equipped with gaskets to seal the case back, crystal, and crown to protect against water infiltration during normal wear. It is important to have the gaskets checked every two years to maintain the water resistance of the watch.
Gear Train
The system of gears which transmits power from the mainspring to the escapement.
Geneva Seal
Quality seal that displays the City of Geneva coat of arms. Watches must meet eleven strict criteria to be awarded the Geneva seal.
GMT Greenwich Mean Time (GMT)
a watch that has the capability of displaying two different time zones.
Grande Sonnerie
A type of repeater that sounds the hours and quarter hours when the wearer pushes the button.
A style of intricate engraving that is popular on watch dials, usually very thin lines interwoven to create a surface texture.
A feature that stops the second hand when the stem is pulled out as far as it will go and allows you to set the exact time.
A stamped code on precious metals to pinpoint its origin and authenticity.
Hard Metal
A scratch resistant metal comprised of binding several materials, including titanium and tungsten carbide, which are then pressed into an extremely hard metal and polished with diamond powder to add brilliance.
Helium Escape Valve. Developed by Rolex alongside the commercial diving company COMEX, the HEV was an automatic valve that allowed gas to escape from a watch during decompression to prevent the crystal from popping off.
High-Tech Ceramic
Used as a protective shield for spacecraft re-entering the earth's atmosphere, high-tech ceramic is polished with diamond dust to create a highly polished finish. Because the ceramic can be injection moulded, pieces can be contoured. It has a very smooth surface and is usually found in black, but can be produced in a spectrum of colours.
The science of time measurement, including the art of designing and constructing the timepieces.
A brand of shock absorber for mechanical watches designed to protect pinions or jewels.
An hour indicator on an analogue watch dial, used instead of numerals.
Integrated Bracelet
A watch bracelet that is integrated into the design of the case.
Synthetic sapphires or rubies that acts as bearings for gears in the mechanical watch, reducing friction.
Jump Hour Indicator
A jump hour indicator takes the place of an hour hand. It usually shows the hours by means of a numeral in a window.
Lap Memory
The ability, in some quartz sport watches, to preserve in the watch's memory the times of laps in a race that have been determined by the lap timer. The wearer can recall these times on a digital display by pushing a button.
Lap Timer
A chronograph function that lets the wearer time segments of a race. At the end of a lap, he/she stops the timer, which then returns to zero to begin timing the next lap.
Limited Editions
A watch style manufactured in a specific amount, often numbered, and available in limited quantities. Limited editions are available from most fine watch manufacturers and may be highly prized by collectors.
Liquid-Crystal Display
A digital watch display that shows the time electronically by means of the liquid held in a thin layer between two transparent plates.
Projection on the watch face to which the watch band/bracelet is attached.
A material, most commonly a paint, used on watches to produce a visible glow in low light. Historically made with radioactive materials like radium and tritium, now made with non-radioactive materials.
Main Plate
Base plate on which all the other parts of a watch movement are mounted.
The driving spring of a watch or clock, contained in the barrel.
Manual Wind
A manual wind watch must be wound every day by the crown in order to run. Even with that inconvenience, they are still produced by the major houses in Switzerland.
Marine Chronometer
Highly accurate mechanical or electronic timekeeper enclosed in a box (hence the term box chronometer), used for determining the longitude on board ship. Marine chronometers with mechanical movements are mounted on gimbals so that they remain in the horizontal position is necessary for their precision.
Measurement Conversion
A feature, usually consisting of a graduated scale on the watch's bezel, that lets the wearer translate one type of measurement into another -- miles into kilometres, for instance, or pounds into kilograms.
Mechanical Movement
A movement based on a mainspring which is wound by hand; when wound, it slowly unwinds the spring in an even motion. An automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist.
Military or 24-hour time
When time is measured in 24-hour segments. To convert 12-hour time into 24-hour, simply add 12 to any p.m. time. To convert 24-hour time into 12-hour time, subtract 12 from any time 13 to 24.
A window in a watch face that shows which phase the moon is.
The inner mechanism of a watch that keeps time and moves the watch's hand, calendar, etc. Movements are either mechanical or quartz.
A rare and lustrous metal that is slightly whiter than platinum and slightly harder. It is part of the platinum group of metals. Palladium is tarnish resistant, electrically stable and resistant to chemical erosion as well as intense heat.
A device that counts the number of strides taken by the wearer by responding to the impact of the wearer's steps.
Perlage is a surface decoration comprising of an even pattern of partially overlapping dots applied with a quickly rotating grinding drill tip. It consists of small, overlapping circles, and is typically applied to the main plate or bridges.
Perpetual Calendar
A calendar that automatically adjusts for the months' varying length and for leap year. Perpetual calendars, which can be powered by quartz or mechanical movements, are programmed to be accurate until the year 2100. Many watch collectors suggest storing mechanical versions in motorised winding boxes when they aren't being worn in order to maintain the calendar countdown.
One of the rarest of precious metals, platinum also is one of the strongest and heaviest, making it a popular choice for setting gemstone jewellery and watches.
A smooth finish that has mirror-like properties.
Power Reserve
The amount of energy reserve stored up to keep a watch running until it stops. The remaining power is sometimes indicated by a small gauge on the dial.
Power Reserve Indicator
A feature of a mechanical watch that shows how much longer the watch will operate before it must be wound again.
Button that is pressed to work a mechanism
Physical vapor deposition is a thin coating applied to a case to add colour for aesthetic purposes.
Quartz Crystal
A tiny piece of synthetic quartz that oscillates at the rate of 32.768 times a second, dividing time into equal segments.
Quartz Movement
A movement which allows a watch to keep time without being wound. This technology employs the vibrations of a tiny crystal to maintain timing accuracy. The power comes from a battery that must be replaced about every 1.5 years. In recent years, new quartz technology enables the watch to recharge itself without battery replacement. This power is generated via body motion similar to an automatic mechanical watch, or powered by light through a solar cell, or even by body heat. A digital quartz watch has no mechanical parts.
Quickset Date
A feature that allows the date to be independently adjusted via the crown, without having to manually wind the hands through full twenty-four hour periods.
A heavily radioactive material used to produce luminescent paint on watch dials in the early part of the 20th century.
Addition of a second hand to measure split times.
A device that chimes the time when the wearer pushes a button.
A non-circular, linear scale whose indicating hand instantaneously returns to the beginning when it reaches the end.
Rose Gold
A softly hued gold that contains the same metals as yellow gold but with a higher concentration of copper in the alloy. A popular colour in Europe, rose gold in watches is often seen in retro styling or in tri-colour gold versions. Some 18k red gold watches achieve their colour from additional copper in the alloy.
Rotating Bezel
A bezel (the ring surrounding the watch face) that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions.
The part of an automatic watch that winds the movement's main spring.
Bearings with high wear resistance and low friction made from rubies. Modern rubies are synthetic.
Sapphire Crystal
A crystal (the cover that protects the watch face) made of synthetic sapphire, a transparent shatter-resistant, scratch-resistant substance.
Screw-Lock Crown
A crown that can be screwed into the case to make the watch watertight.
Synthetic gaskets that seal the joints between parts of the case and keep out the water.
Second Time-Zone Indicator
An additional dial that can be set to the time in another time zone. It lets the wearer keep track of local time and the time in another country simultaneously.
Shock Absorber
Resilient bearing which, in a watch, is intended to take up the shocks received by the balance staff and thus protects its delicate pivots from damage.
Shock Resistance
Spring-loaded shock protection used on balance wheel-supporting jewels to absorb sudden, potentially damaging impacts.
Skeleton Case
A case with a transparent front or back that allows the wearer to view the watch's movement.
Slide Rule
A rotating bezel that can multiply or divide two numbers, convert miles/KM, convert exchange rates, etc. An example is a dollar to Euro converter to calculate rate of descent or fuel consumption for pilots.
Solar Compass
A compass that lets the wearer determine the geographical poles by means of a rotating bezel. The wearer places the watch so that the hour hand faces the sun. He then takes half the distance between the position and 12 o'clock, and turns the bezel until its "south" marker is at that halfway point. Some quartz watches have solar compasses that show directions on an LCD display.
Solar Powered Batteries
Batteries in a quartz watch that are recharged via solar panels on the watch face.
Stainless Steel
An extremely durable metal alloy that is virtually immune to rust, discoloration and corrosion; it can be highly polished, thus representing a precious metal.
Stepping Motor
The part of a quartz movement that moves the gear train, which in turn moves the watch's hands.
Sterling Silver
A white and highly reflective precious metal. Sterling silver refers to silver that is 92.5 percent pure, which should be stamped on the metal, sometimes accompanied by the initials of the designer or the country of origin as a hallmark. Although less durable than stainless steel and other precious metals, sterling silver is often employed in watches that coordinate or look like sterling silver jewellery.
A watch with a seconds hand that measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stopwatch function and the timepiece are referred to as a chronograph.
Swiss Made
A watch is considered Swiss if its movement was assembled, started, adjusted and controlled by the manufacturer in Switzerland.
Swiss A.O.S.C. (Certificate of Origin)
A mark identifying a watch that is assembled in Switzerland with components of Swiss origin.
Sweep Seconds-Hand
A seconds-hand that is mounted in the centre of the watch dial.
A tachometer, also referred to as a Tachymetre, is a graduation on dial of a chronograph which enables one to determine average speeds or hourly production on the basis of an observation period of under sixty seconds.
Instrument used for registering intervals of time, without any indication of the time of day.
The "space age" metal, often used with a silver-grey appearance. Because it is 30% stronger and nearly 50% lighter than steel it has been increasingly used in watchmaking, especially sport watch styles. Its resistance to salt water corrosion makes it particularly useful in diver's watches.
A device in a mechanical watch that eliminates timekeeping errors cause by the slight difference in the rates at which a watch runs in the horizontal and vertical positions. The tourbillon consist of round carriage, or cage, holding the escapement and the balance. It rotates continuously at the rate of once per minute.
A slightly radioactive substance that collects light and is used to allow the hands or hour markers to glow in the dark. The radiation is so low that there is no health risk. Watches bearing tritium must be marked as such, with the letter T on the dial near 6 o'clock.
Two Tone
A watch that combines two metals, usually yellow gold and stainless steel in the case of fine watches.
Uni-directional Rotating Bezel
A bezel that indicates elapsed time, often found on divers watches. It moves only in a counter-clockwise direction.
Coordinated universal time. The official standard of national time, based on GMT.
Movement of a pendulum or other oscillating element, limited by two consecutive extreme positions. The balance of a mechanical watch generally makes five or six vibrations per second (i.e. 18,000 or 21,600 per hour), but that of a high-frequency watch may make seven, eight or even ten vibrations per second (i.e. 25,200, 28,800 or 36, 000 per hour).
A misused term. No watch is fully 100% waterproof.
Water Resistance
Ability of a watch to withstand water from entering the case. A water resistant watch can handle light moisture, such as a rain or sink splashes, but should not be worn swimming or diving. If the watch can be submerged in water, it must state at what depth it maintains water resistance, i.e. 50 meters or more on most sport watches. Below 200 meters, the watch may be used for skin diving and even scuba diving depending upon the indicated depths.
Also referred to as a pinion, the wheel is a circular part that revolves around an axis to transmit power.
White Gold
Created from yellow gold by incorporating either nickel or palladium to the alloy to achieve a white colour. Most watches made of white gold will be 18k.
Operation consisting in tightening the mainspring of a watch. This can be done by hand (by means of the crown) or automatically (by means of a rotor, which is caused to swing by the movements of the wearer's arm).
Yacht Timer
A countdown timer that sounds warning signals during the countdown to a boat race.