When shopping for a new watch, you may come across terms that are new to you. Knowing some basic watch vocabulary can help you shop like an expert. This watch glossary gives you the tools to buy watches that fit perfectly into your life.
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 indicates the stopwatch function, and 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. Watchmakers use these units to denote water resistance. Please see the definition for water resistance.
Automatic movement: An automatic movement is a 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 mainspring of the winding system.
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 directions.
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 35 millimeters or more in diameter; the size for a women's watch case is 34 millimeters 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 watch may have a hidden hand or a separate dial to measure 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. Calendars, stopwatches, alarms, and other extras are complications.
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 and displays the time zones for many cities or countries. The circle is shaded to specify daytime and nighttime hours.
Depth sensor: This function is found on some dive watches and determines depth by measuring water pressure.
Dive watch: A dive 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.
Dual time: This function allows the user to keep track of the time in two time 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.
Gasket: Gaskets are seals placed on the crown, buttons, case back, and crystals to increase the water-resistant 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, usually in a subdial, 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.
Kinetic: In watch terminology, kinetic refers to a watch mechanism or battery that is powered by the natural movements of the wearer's arm. A kinetic watch uses oscillating weights to generate the power that charges the 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.
Mainspring: The mainspring 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 the mainspring 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.
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, it is the watch's engine. Watches have quartz, mechanical, or automatic movements.
Perpetual calendar: The perpetual calendar automatically resets the day at the end of the month or year, accounting for 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.
Pulsimeter: The pulsimeter is 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 a 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.
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 features scales and markings that the wearer uses to calculate timekeeping or mathematical equations. These bezels are usually designated as bi-directional rotating bezels or unidirectional rotating bezels.
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 3 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 fly-back hand can be stopped independently to note a point in time while the other hand continues to move. The fly-back 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.
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 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.
Unidirectional rotating bezel: This bezel turns in only one direction.
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 see 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 submerged in water. A watch that has a rating of 10 ATM is water-resistant to 100 meters, and one that has a rating of 20 ATM is water-resistant to 200 meters. These ratings are often found on dive watches.
World time dial: Generally found on the bezel or outer rim of the main dial, a world-time dial is a scale that indicates the time in many time zones. Each time zone lists a major city.