Watches Glossary

Accuracy: Refers to a watch’s precision.

Alarm Watch: Incorporates a movement that releases an acoustic sound at a set time. Alarm watches generally have a second crown dedicated to the winding, setting, and release of the striking work, which is indicated by an additional center hand.

Analog Watch (also spelled analogue): A watch that displays time indications by use of watch hands on a dial.

Analog Quartz Watch: An analog timepiece operating on a battery, or by solar power, regulated by a quartz crystal.

Anti-magnetic: A watch whose movement is not affected by electromagnetic fields that influence two or more windings of the balance spring, causing them to stick together, thus accelerating the rate of the watch and disturbing its time-keeping accuracy.

Anti-reflection or Anti-reflective: Superficial glass treatment that disperses reflected light.

Arbor: Bearing element of a gear or balance whose pivots run in jewel holes or brass bushings.

Aperture: Small dial opening in which certain indications are given, such as date and hour.
 
Appliqué: Numerals or symbols cut out of sheet metal and stuck or riveted to a dial.

Assembling: The process of fitting together the components of a movement.

Atmosphere: Unit of measure that indicates a watch’s water resistance.
 
Atomic Watch: The U.S. Government owns and operates the F-1 U.S. Atomic Clock, located in Boulder, Colorado. This clock is accurate to the second and will neither gain nor lose a second in 30 million years. The Atomic Clock sends out signals that can be picked up by watches equipped with the right type of crystal. These watches boast the most accurate time and never have to be reset.
 
Automatic: A watch whose mainspring is wound by the movements or accelerations of the wearer's arm. Also called a self-winding or kinetic watch. Abraham-Louis Perrelet invented the system in Switzerland in the 18th century.

Auto Repeat Timer: Permits the continuous operation of a countdown timer. Once the timer is set, it will begin to countdown to zero. It will beep a warning signal, return to the preset time, and start the countdown again until the stop button is pressed.

Balance: An oscillating device that works with the balance spring to determine the frequency of a watch movement’s functioning and precision.

Balance Spring: Component that determines a watch movement’s precision.

Barrel: Cylindrical box that contains a watch’s mainspring.

Battery Life: Minimum period of time that a battery powers a watch. Battery life is counted from the moment a factory installs the battery.

Bearing: Part of the watch on which a pivot turns. In jeweled watches, the pivots are jeweled to reduce friction and wear.

Beveling: Treatment found in higher-grade watch movements in which the edges of levers, bridges, and other elements are beveled or edged by 45 degrees.

Bezel: Frame of a watch that surrounds the dial and crystal. The bezel may be integrated with the case middle or a separate element snapped or screwed onto the middle. There are various types of bezels:

• Compass Bezel: Bezel that can be used to fix an approximate direction by
  directing the hour hand toward the sun and turning the bezel so that the “S”
  mark is positioned halfway between the hour hand and the 12 o’clock position.

• Rotating Bezel Switch: Bezel that can be turned to reveal a different display on
  the watch.

• Rotating Elapsed-time Bezel: Graduated rotating bezel that tracks periods of
  time. Turns to align the zero on the bezel with the seconds or minute hand. The
  elapsed time can be read off the bezel.

Cabochon: Any kind of gemstone polished and uncut; usually half-spherical shape that’s used mainly as an ornament on the winding crown or on certain elements of a watchcase. Cabochons may also be synthetic gemstones.

Calendar (annual): Intermediate complication between a simple and perpetual calendar. Feature correctly displays all the months with 30 or 31 days, but must be manually adjusted in February.

Calendar (full): Displays month, date, and day of the week on the watch dial, but needs a manual correction at the end of any month with less than 31 days; generally combined with a moon phase.

Calendar (perpetual): Most complex complication related to the calendar feature. Indicates month, date, day, and leap year. Does not require manual corrections until the year 2100 (when the leap year will be ignored).

Calibre: Originally the size and factory number of a given watch movement, this term now denotes a type of movement. When a calibre number is accompanied by the manufacturer's mark, it serves as an indication of origin.

Carousel: Device similar to the tourbillon, but driven by the third wheel, not the fourth.

Carriage or Tourbillon Carriage: Essential for the perfect balance of a watch’s entire system and stability. Today’s tourbillon carriages make one rotation per minute. Errors of rate in the vertical position are eliminated. With the popularity of transparent dials, carriages became aesthetic elements.
 
Case: Container that protects the watch movement from dust, damp, and shocks. Made up of three parts: middle, bezel, and back.

Center Second Hand: Also called a sweep seconds hand.

Center Wheel: It is a minute wheel.

Chime: Striking mechanism equipped with bells that may strike a tone or play a complete melody. A watch with this feature is also called a chiming watch.

Chapter Ring: Hour circle; the hour numerals arranged on a dial.

Chronograph: Watch with a built-in stopwatch function or timer that can be started and stopped to time an event. Counters can register seconds, minutes, and hours. Can be started and stopped as desired. This is not the same as a stopwatch or chronometer.

Chronometer: High-precision watch that has undergone a series of precision tests by an official institute. The requirements are very severe: a few seconds per day in the most unfavorable temperature conditions (for mechanical watches) and positions that are ordinarily encountered. A watch cannot be called a chronometer unless each individual piece has passed a series of tests and has been issued a running bulletin and chronometer certificate from an acknowledged Swiss control authority.

Clasps: There are a number of clasp types commonly used by the watch industry. The most common include:

• Deployment Buckle (also known as a fold-over buckle): Three-folding closure   that secures two ends of a bracelet. When closed, the buckle covers the folding   mechanism.

• Hook-lock: Composed of two separate elements, each fitting at either end of a   bracelet. One end hooks into the other to secure the bracelet on the wrist.

• Jeweler’s Clasp: Allows the watch to lie flat.

• Sliding Clasp: Similar to a hook-lock, but has a sliding mechanism that allows   for easy sizing by sliding up the band.

• Twist-lock: Similar to a jeweler’s clasp, it’s used on ladies jewelry bracelets.

Cloisonné: Type of enamel work. Outlines are drawn with thin metal wires, and colored enamels fill the hollows formed. After oven firing, the surface is smoothed until the threads appear again; mainly used for dial decoration.

Column Wheel: Part of a chronograph’s movements, it governs the functions of various levers and parts of the chronograph’s operation; very precise. Generally the preferred type of chronograph operation.

Complication: Additional function to the basic watch movement (like moon phase, power reserve, GMT and full calendar, perpetual calendar, split seconds, chronograph, tourbillon device, minute repeater, etc.).
 
Crown: Knob located on the outside of a watch case that’s used for winding the mainspring. Also used for setting the hands to the right time and for correcting calendar indications.

Date Watch: Watch indicating the month, date, and, sometimes, year and phases of the moon. (See Calendar Watch entries.)

Dial: Face of the watch on which time and other functions are displayed. Functions are given by means of numerals, divisions, or symbols of various types.

Digital: Watch whose indications are displayed inside a window on the watch dial. There are two basic types of digital watches:

• Liquid Crystal Display (LCD): Digital watch display showing time electronically   by means of a liquid in a thin layer between two transparent plates. All LCD   watches have quartz movements.

• Light Emitting Diode (LED): Digital watch display showing time at the push of a button.

Direct-drive: Refers to a seconds hand that moves forward in little jerks, unlike the smoother movement of a sweep seconds hand. Trotteuse is the French term for a direct-drive seconds hand (especially a center seconds hand).

Diver’s Watch: Watch that determines the wearer's water submersion depth by measuring water pressure. Can display depth by either analog hands and a scale on the watch face, or through a digital display. Diver’s watches must meet certain critical standards regarding the effect of water on watch mechanisms. These standards include: watch’s water resistance, pressure resistance, underwater readability, anti-magnetic and anti-shock capabilities, rust resistance in salt water, the ability to withstand sudden temperature changes, etc. A diver’s watch must also include a rotating elapsed-time bezel.

Escape Wheel: Wheel that’s part of the escapement mechanism.

Escapement: Positioned between the train and the balance wheel, the escapement governs the rotation speed of a watch’s wheel-train wheels. Today, the most common type of escapement is the lever escapement.

Fly-back: Function originally developed to meet the needs of pilots. This feature, combined with chronograph functions, allows a new measurement starting from zero by pressing down a single device. The fly-back is an additional center second hand that can remain superimposed on the other one as it moves. It can be stopped independently and then made to "fly back" to catch up with the other hand. It can be stopped and reset to zero together with the other hand.

Frequency: The number of cycles per time unit. It’s defined as the number of oscillations of a balance every two seconds or of its vibrations per second. Usually expressed as vibrations per hour.

Glass, Crystal: Thin plate of glass or transparent synthetic material that protects watch dials.

GMT (Greenwich Mean Time): A watch with GMT displays two or more time zones. GMT refers to solar time at the original site of the Royal Observatory in Greenwich, England, which is located on the prime meridian.

Hammer: Steel or brass element used in watch movements provided with a repeater or alarm.

INCABLOC: This means that it’s shockproof.

Lug: Extension of the case middle by which a strap or bracelet is attached.

Main Plate Base: Plate on which all the other parts of a watch movement are mounted.

Mainspring: Driving spring of a movement that stores and transmits the power required by a watch to function.

Manual: Movement in which winding is performed by hand.

Markers: Elements that have been printed or applied to the dial. Used as reference points for the hands to indicate hours and minute intervals.

Mean Time: Refers to the mean time of the meridian of the Greenwich Observatory in Greenwich, England. Considered to be the universal meridian and is used as a standard of the civil time system. Mean time is counted from midnight to midnight.

Mechanical: Watch movement with a balance wheel.

Middle (of watchcase): Middle part of the case in which the movement is fitted.

Module: Self-contained mechanism added to a movement to provide an additional function.

Moon Phase: Function that is usually combined with calendar-related features. A moon phase disc advances one tooth every 24 hours. While highly accurate, most watches with moon phases must be manually adjusted every two-and-a-half years to recover a lost day. Some timepieces are calculated so accurately, that the manual correction would be required only once a century.

Movement: Entire mechanism of a watch or clock, including the winding and setting mechanism, the mainspring, the train, the escapement, and the regulating elements. Movements are divided into two large families: quartz and mechanical.

Oscillation: Rotation movement of a watch balance, formed by two vibrations.

Pinion: Has less teeth than a wheel; transmits the motive force to the wheel, combining with it and an arbor to form a gear. Pinion teeth are highly polished to reduce friction to a minimum. There are usually six to 14 pinion teeth.

Pivot: End of an arbor (the bearing element of a gear or balance) that turns on a jewel support. Their shape and size can influence friction and, as a result, the pivots of the balance staff are very thin and fragile, thus protected by a shockproof system.

Plated: A metal treated by a galvanizing process that applies a layer of gold or other precious metal on a brass or steel base.

Plexiglas: A synthetic resin that can be used for watch crystal.

Power Reserve: Duration in hours of the mainspring’s running time after it has achieved winding peak.

Power Reserve Indicator: Feature on a mechanical watch indicating how much longer a watch can be worn before it needs to be rewound. On a quartz watch, a battery reserve indicator signals that the battery is low.

Precision: Refers to a watch’s accuracy rate. Generally a precision watch is a chronometer with an accuracy standard certified by an official watch-rating bureau. A high-precision watch is a chronometer that has been certified by an observatory.

Pulsimeter Chronograph: Scale that shows the number of pulse beats per minute.

Pusher, Push-piece, or Push Button: Plunger with a head that projects from the center of a watchcase; operated by a finger to set time.

Ratchet (Wheel): A toothed wheel held in place by a click and pressed down by a spring.

Regulating Elements: Sprung balance and the escapement (escape wheel, lever, and roller).

Regulator: Lengthens and shortens the active section of the balance spring, thus regulating the movement’s functioning. Also refers to a type of clock used for time comparisons in setting or regulating other timepieces.

Repeater Watch: Strikes the hours via a mechanism operated by a push-piece or bolt. There are various types of repeaters:

• Quarter-repeater: Sounds a low note for the hours and a "ding-dong" for each of the quarters.
• Five-minute Repeater: Strikes the hours, quarters, and five-minute periods after the quarter.
• Minute-repeater: Strikes the hours, quarters, and minutes.
• Grande Sonnerie (Grand Strike): Automatically strikes the hours and quarters, and will repeat when a push-piece is pressed down.
• Chiming Repeater: Quarters are struck on three or four gongs of different pitch.

Resistor: A coil or conductor in electrical timepieces that resists electrical flow; measured in ohms.

Retrograde: Refers to watch hands that move on an arc scale (of 90 to 180) instead of making a revolution of 360 before starting a new measurement. Generally, retrograde hands are used to indicate month, date, or day in perpetual calendars, but there are also timepieces with retrograde hours, minutes, or seconds. A retrograde watch requires the insertion of a special mechanism into the basic movement.

Rotor: Found in automatic winding mechanical movements, it is the part that, either via complete or partial revolutions, or the movement of the human arm, winds the mainspring.

Sapphire Crystal: Made of synthetic sapphire, it is a transparent, shatter resistant, scratch-resistant cover to protect the face of the watch.

Screw-lock Crown: A crown that can be screwed into the case to make the watch watertight.

Second Time-zone Indicator: An additional dial that can be set to time in another zone.

Self-winding: This means it is automatic.

Shock Absorber: A resilient bearing designed to take up the shocks received by a watch’s balance staff; protects the fragile pivots from damage.

Shockproof or Shock-resistant: Refers to watches provided with shock absorber systems that help prevent damage from shocks to the balance pivots.

Skeleton Watch: A watch in which the case and various parts of the movement are of transparent material, enabling the main parts of the watch to be seen.

Small Second: A time display in which the second hand is placed inside a small subdial.

Solar or Light-powered Watches: Watches whose mechanisms are powered by light is stored via solar cells and placed within the watch. The light knocks loose electrons in the solar cell, thus creating electrical current. This current is then stored in the watch’s quartz battery, which powers the watch.

Split-second Hand: Comprising two hands; one a fly-back hand, the other a regular chronograph hand. When the chronograph is set, both hands move together. The fly-back hand can be stopped independently for the purpose of timing laps or finishing times.

Striking-work, Striking-mechanism: The automatic or hand-operated mechanism that strikes the hours, minutes, etc., or that rings an alarm bell.

Sweep Seconds Hand: Mounted in the center of the watch dial.

Tachometer or Tachymeter: The most common additional feature on chronographs. It is an instrument for measuring the speed of a moving object over a known distance.

Telemeter: Determines the distance of an object from the observer by measuring how long it takes sound to travel the distance. The dial's markings are based on the distance that sound travels per second: 1,115 feet per second.

Third Wheel: The wheel positioned between the minutes and seconds wheels.

30-minute Recorder: The subdial on a chronograph that can time periods of up to 30-minute intervals.

Timer: Used for registering intervals of time without any indication of the time of day.

Tonneau: Refers to a particular watchcase shape that imitates the profile of a barrel.

Totalizer: Keeps track of elapsed time and displays it on a subdial or subdials on the watch face. Also refers to any counter on a watch, such as a stroke counter on a golf watch.

Tourbillon Device: Invented in 1801 by A. L. Breguet to eliminate errors of rate in the vertical positions. In a mechanical watch, it eliminates timekeeping errors caused by the slight differences in rates at which a watch runs in the horizontal and vertical positions. Rotates continuously at the rate of once per minute; The case makes one revolution per minute.

Train: All of the wheels between a movement’s barrel and its escapement.

Transmission Wheel: Another term for crown wheel.

12-hour Recorder (or Register): Subdial on a chronograph that can time periods of up to 12 hours.

Water Resistance: A watch constructed to prevent water or moisture from entering the watch. The watch’s ability to withstand splashes of water and the depth to which a watch can be worn underwater. Measured in atmospheres. There are various degrees of water resistance:

• Water Resistant: Will withstand water splashes, but not immersion.
• Water Tested to 50 Meters (165 feet): Can be worn in the shower or when swimming in shallow water.
• Water Tested to 100 Meters (330 feet): Can be worn snorkeling or swimming.
• Water Tested to 150 Meters (500 feet): Can be worn snorkeling.
• Water Tested to 200 Meters (660 feet): Can be worn skindiving.
• Diver’s to 150 Meters (500 feet): Meets ISO Standards and can be worn scuba diving.
• Diver’s to 200 Meters (660 feet): Meets ISO Standards and can be worn scuba diving.

Water-resistant Case: A watchcase whose joints are made to prevent moisture from entering.

Wheel: A circular element that combines with an arbor and a pinion to make a gear; normally made of brass. The wheels between the barrel and the escapement make up the train.

Winding Operation: An operation that consists of tightening the mainspring of a watch. This can be accomplished by hand (by use of the crown) or automatically (by means of a rotor, which is caused to swing by the movements of the wearer's arm).

Winding Stem: The watch element that transmits motion from the crown to the gears that directs the manual winding and setting of a watch.

Window: Refers to an aperture in the dial that allows the wearer to read the underlying indication such as the date or a second zone’s time or jumping hour.

World Time: This is an additional feature of watches provided with a GMT function. It displays the 24 time zones on the dial or the bezel with each zone identified by a city name, thus allowing instantaneous reading of the time in any country.

Zodiac: Refers to a circular belt with an ecliptic in the middle that contains the 12 constellations through which the sun appears to pass over the course of a year.