Watches are amazing examples of engineering and artistic skill with many convenient functions; therefore, the world of watchmaking has a specialized terminology. When shopping for a new watch, be it wrist watch or pocket watch, you may find terms that are new to you or that are similar to other terms ? this can make comparing watches a bit confusing. On the other hand, there are so many watches available that you can find your perfect timepiece when you know the vocabulary. This dictionary of watch terms provides definitions for the many features of contemporary watches.
Alarm: Watches can have daily, hourly and 12-hour alarms, and many multifunction watches have more than one alarm.
Alpha hands: Alpha hands are slender and have a slightly tapered design.
Altimeter: The altimeter function determines altitude by measuring changes in barometric pressure. An altimeter is a common feature in a pilots' watch.
Analog: An analog watch displays the time with a dial, hands and numbers or hour markers; this is the traditional dial.
Analog chronograph: This chronograph watch displays both the time and stopwatch functions with analog hands on a dial. The center hand will indicate the stopwatch functions while the seconds display in a subdial. Quartz watches with analog chronograph function often display 1/10th seconds and 1/100th seconds in subdials.
Analog digital: This watch style has an analog dial with hands and a separate digital display. The two displays usually operate independently of each other.
Aperture: A window set in a watch dial that displays a function, an aperture most often displays the calendar date, weekday or month.
ATM: An ATM is a unit of atmospheric pressure. Watch makers use these units to denote water resistance. See the definition for water resistance.
Automatic movement: Basically, an automatic movement is mechanical movement with a self-winding design. An automatic watch harnesses the energy produced by motion to wind the spring. This movement features a rotor that spins when the watch is in motion as when the wearer moves his arm. The mechanism transfers the energy from the spinning rotor to the main spring of the winding system. Other terms that refer to automatic movement are automatic watch, automatic winding and self-winding movement.
Band: A band is the cuff that wraps the wrist and is attached to the case. On Overstock.com, metal and ceramic bands with links are called bracelets, while leather, rubber or fabric bands are called straps. Some women's watches have fashionable bangles.
Baton hands: Batons are straight, narrow hands that are also referred to as stick hands.
Bezel: The bezel is a ring that attaches the crystal to the watch case.
Bi-directional rotating bezel: This bezel turns in both the clockwise and the counterclockwise direction. Also, see the definition for rotating bezel.
Cabochon: A cabochon is a decorative bead, often a gemstone, with a smooth, domed shape.
Calendar: The calendar is a function that displays the day, date and/or year in addition to the hour. Analog watch dials show this feature in apertures or subdials.
Caliber: Caliber refers to the configuration and size of the watch movement.
Case: The frame that houses the watch mechanisms is called the case. The case for a men's watch usually measures at 35 mm or more in diameter; the size for a women's watch case is 34 mm or less.
Case back: Case back is the term for the removable cover on the watch case that allows access to the internal mechanism of a watch.
Chronograph: A chronograph watch has a stopwatch and can measure specific durations of time, often in fractions of a second. The long hand that is centered on the dial and used as the seconds hand on conventional watches is usually a stopwatch hand on chronographs. Subdials and digital displays also register the times. Some chronographs can measure more than one event at a time.
Chronometer: A chronometer is a high-precision timepiece whose movement has been quality-tested by the Controle Officiel Suisse des Chronometres [COSC], a Swiss laboratory. The COSC tests the movement at five different positions and three different temperatures for several consecutive days to determine accuracy. Timepieces qualifying as chronometers include a COSC certification number.
Complication: The term "complication" refers to any watch function other than the basic timekeeping function, e.g. calendars, stopwatches, alarms and other extras.
Countdown timer: A countdown timer is a watch function that measures how much of a preset duration of time has passed.
Crown: Also called the winding stem, the crown is a button on the side of the case that adjusts the time and date. The crown also winds the movement of mechanical watches.
Crystal: The crystal is the clear protective panel set over the watch dial; it is usually a Plexiglas or mineral disc. Hardlex, a heat-treated mineral crystal, and synthetic sapphire crystals are especially scratch-resistant.
Dauphine hands: These hands are wide at one end and taper to a fine point. They also have a crease down the center.
Day and night indicator: This indicator encircles the dial rim or the bezel of a watch that displays the time zones for many cities or countries. The circle is shaded to show which time zones are in the daylight or nighttime part of the day.
Depth sensor: This function of some divers' watches determines depth by measuring water pressure.
Dial: The face of a watch case that displays the timekeeping functions is called a dial.
Digital dial: This dial indicates the time and other features in a liquid crystal display (LCD) or light emitting diode (LED) display. The feature is especially useful displaying detailed information on a multifunction watch and is a popular feature of sport watches.
Diver's watch: A diver's watch is suitable for snorkeling or scuba diving. These dive watches pass International Standardization Organization (ISO) regulations and must have a water resistance rating of 20 ATM (200 meters/660 feet).
Double chronograph: A double chronograph watch features two independent stopwatches. The stopwatch function can time two events simultaneously.
Dual time: This function allows the user to keep track of the time in two times zones at once. The display can have two dials: a subdial placed in the main dial or analog and digital displays on the same dial.
Elapsed-time bezel: Elapsed-time function refers to a register displayed on a rotating bezel that measures the distance covered over a specific period of time.
Escapement: The escapement is a device that controls the motion and speed of the gear train in a mechanical watch movement.
Face: The watch dial with its hands, numbers and other features is often referred to as the face.
Flyback hand: This is an extra hand, set on the dial, which along with the seconds hand performs the splits-second function of measuring intervals. See the definition for split-seconds chronograph.
Gasket: Gaskets are seals placed on the crown, buttons, case back and crystals to increase the water resistance abilities of a watch. The gaskets should be checked for deterioration by a professional jeweler every few years.
Guilloche: The guilloche design features a pattern of ridges that ripple outward from the center of a flat surface; it is also called a sunburst pattern. This texture is common on the dials of fine watches.
Horology: Horology is the history and craft of making watches, clocks and other devices for measuring time.
Hour recorder: The recorder measures and displays, in a subdial, up to a specific period of time. The most common recorders are 12-hour, 60-minute and 30-minute registers.
Index markers: An index, indices for the plural, is a stick-shaped marker that takes the place of a number on a dial.
Jewels: The term "jewels" refers to the bearings in a mechanical or automatic movement. A mechanical movement generally will have at least 17 jewels. Traditionally, watchmakers used natural gemstones for the bearings; however, today's watches generally have bearings made of synthetic ruby.
Jump hour: A jump-hour function displays the hour in an aperture instead of with a hand on the main dial. The number in the aperture window "jumps" to the next hour as the time changes. Often, the main dial still displays the minutes and hours with hands.
Kinetic: In watch terminology, kinetic refers to a watch mechanism or battery that is powered by the natural movements of the wearer's arm. For example, a quartz watch with kinetic-powered movement never needs a new battery.
Lap timer: A watch function that measures segments of a race, a lap timer can be set to show the time for each lap without losing track of the total race time.
Lap time memory: Some sport watches have the ability to store lap times that can later be recalled by the user. A lap time memory will be found in a quartz watch with digital display.
Lugs: Lugs are the stubs on a watch case that provide the point of attachment for the band.
Main plate: A watch movement is mounted on a base panel called the main plate.
Main spring: The main spring in a movement is the spring that powers the watch functions as it unwinds to release energy.
Mechanical movement: The most important feature of a mechanical movement is that the main spring that must be manually wound to store potential energy. This spring unwinds slowly, releasing energy to move the gears that power the watch's timekeeping functions. This movement is sometimes referred to as manual winding.
Military time/24-hour time: Many watches have a subdial, scale or digital function for tracking time in the 24-hour format in addition to the 12-hour format. The 24-hour format is also known as military time.
Moon phase dial: This is a function that tracks and displays the phases of the lunar month, usually in a subdial. Some watches have a sun-and-moon subdial which tracks the 24-hour day.
Movement: In the science of watchmaking, movement refers to the interior mechanism of the watch that drives the timekeeping functions; in other words, the watch engine. Watches have quartz, mechanical or automatic movements. For more information, read our watch movement buying guide.
Perpetual calendar: The perpetual calendar automatically resets the day at the end of the month or year, including during leap years, to keep a timepiece's calendar accurate.
Power reserve: Power reserve is the amount of energy that a watch has stored in its movement. The average mechanical or automatic watch has a full power reserve of about 36 hours.
Power reserve indicator: This function uses a subdial or aperture to display the hours of energy a watch has in power reserve.
Pulsimeter: A function of advanced sport watches that measures the wearer's pulse rate.
Quartz crystal: This crystal is a piece of quartz, usually synthetic, that is used as the oscillator that drives the timekeeping functions of a quartz watch.
Quartz movement: A battery powers quartz movement. The movement is called quartz because the battery works in combination with a quartz crystal. The battery passes an electric current through the crystal to keep it oscillating at over 32,000 vibrations per second. This vibrating crystal drives a step motor that moves the watch hands at a constant rate to keep time accurately.
Rattapante: This is the French term for splits-second chronograph function.
Register: Register is an alternative word for subdial.
Rotating bezel: This type of bezel can be turned and set to different positions by the watch wearer. A rotating dial often feature scales and markings that the wearer uses to calculate timekeeping or mathematical equations. These bezels are usually designated as a bi-directional rotating bezel or a uni-directional rotating bezel.
Screw-down crown: This crown fits into the watch case to create a stronger seal than a push-and-pull crown. These crowns help create greater water resistance for the timepiece. To close a screw-down crown, press it against the case while turning in a clockwise direction.
Shock resistance: Shock resistance refers to the durability of the watch case and its ability to protect the movement and complications. To be considered shock resistant, a watch must be able to survive being dropped onto a wooden floor from a height of three feet or withstand an impact of equal strength.
Skeleton case: This case design displays the watch movement with an open-cut dial or with a clear crystal placed on the case back. The design highlights the intricate skill involved in making watch movements.
Solar-powered watch: A solar-powered quartz watch has solar panels on the case that recharge the battery.
Split-seconds chronograph: This function allows two hands to measure specific amounts of time and the intervals. The hands move together, but one hand, called the flyback hand can be stopped independently to note a point in time while the other hand continues to move. The flyback hand can then be started again and will "fly back" to catch up to the first hand. This function can be used as a lap timer.
Stopwatch: A timepiece or timing function that can be started and stopped instantly to measure an exact period of time, often to a fraction of a second. The stopwatch is usually displayed by a hand on the analog dial, but is also found in digital display watches. A watch with a stopwatch complication is called a chronograph.
Subdial: The smaller registers set in the main dial of a watch face are called subdials.
Sweep hand: The long hand that denotes the seconds as it moves around the dial of an automatic watch is called the sweep hand. Also called the sweep second hand, this marker moves in a smooth arc on the dial. The second hand of a quartz watch will click forward in second-long increments.
Swiss-made movement: A Swiss-made movement must have Swiss parts, be assembled in Switzerland and then be placed in the case at a Swiss factory. The case itself does not need to be manufactured in Switzerland, although most high-end watches feature Swiss-made cases.
Tachymeter: A tachymeter is a scale used to measure the speed traveled over a specific distance. The scale used for making this calculation is often found on the bezel or the dial rim of a timepiece.
Telemeter: A telemeter determines how long it takes a sound to travel between the watch and a specific object. This measurement is then used to determine the distance between the two points. The telemeter scale is usually set on the bezel.
Tonneau case: Tonneau is a shape for watch cases that has convex sides and resembles the side view of a barrel.
Tourbillion: A tourbillion is a frame for the escapement section of a mechanical watch. Some watches have a window for viewing the tourbillion as an aesthetic element.
Uni-directional rotating bezel: This bezel turns in only one direction. Also, see the definition for rotating bezel.
Waterproof: This term is misleading when applied to watches. No watch is 100 percent waterproof, however many watches have a high water resistance rating and may be labeled thus. Please read the definition for water resistance.
Water resistance: The design of a water-resistant watch helps prevent moisture from entering the case and harming the movement. Rubber, nylon or Teflon gaskets on the case back, crystals, crowns and push buttons seal these crucial points. Water resistance is tested in measurements of atmosphere (ATM). Each ATM denotes 10 meters of static water pressure. Many watch cases will list the basic measurement of 1 ATM as "water resistant." These watches will withstand small splashes of water but should not be worn while washing the hands or submerging the hands in water. For more information, read our watch buying guide.
World time: Found in digital watches, this function features a list of the current times in major cities around the world.
World time dial: A world-time dial is a scale generally found on the bezel or outer rim of the main dial that indicates the time in many time zones, up to 24. Each time zone lists a major city.
Yacht timer: This countdown timer features alarms to warn of the time elapsed during the countdown to a yacht race.
