Automatic movement
A mechanical watch movement wound by the movement of the wearer's wrist. It uses a rotor and mainspring rather than a battery.
Explore related watches or advice →HARBOR2ARBOR WATCH EDUCATION
Watch Glossary: Horology Terms Explained
From automatic movements and watch calibers to chronographs, bezels and case sizing, use this original guide to understand the words found in watch descriptions before you buy.
60 practical watchmaking, collecting and buying terms
Watch movements and mechanisms
Quartz movement
A movement that uses a battery or another electrical power source and a quartz crystal to regulate timekeeping.
Explore related watches or advice →Mechanical watch
A watch powered by a wound mainspring and a train of gears, rather than a conventional quartz timing circuit.
Explore related watches or advice →Manual-wind watch
A mechanical watch whose mainspring is wound by turning the crown instead of relying on an automatic rotor.
Explore related watches or advice →Caliber
The designation for a movement design or movement family. Caliber numbers help identify specifications and service parts.
Explore related watches or advice →Rotor
A moving weight inside an automatic movement that turns with wrist motion to help wind the mainspring.
Explore related watches or advice →Mainspring
The coiled spring that stores energy in a mechanical watch and releases it through the gear train.
Explore related watches or advice →Escapement
The mechanism that regulates how the movement releases stored energy to keep the watch running at a controlled pace.
Explore related watches or advice →Balance wheel
An oscillating component in many mechanical movements that works with the hairspring to regulate timing.
Explore related watches or advice →Hairspring
A fine spring attached to a balance wheel that helps govern its back-and-forth motion.
Explore related watches or advice →Jewels
Usually synthetic ruby bearings placed at selected movement contact points to reduce friction and wear.
Explore related watches or advice →Power reserve
How long a fully wound mechanical watch can keep running without additional winding. Actual duration varies by caliber.
Explore related watches or advice →Hacking seconds
A feature that stops the seconds hand when the crown is pulled to the time-setting position, making synchronization easier.
Explore related watches or advice →Hand-winding
The act of winding a mechanical watch by turning its crown. Some automatic calibers also support hand-winding.
Explore related watches or advice →Beat rate
How frequently a mechanical balance oscillates, often expressed as vibrations per hour (vph) or hertz (Hz).
Explore related watches or advice →Watch case, crystal and fit
Case
The exterior housing that protects the watch movement and supports the crystal, crown and caseback.
Explore related watches or advice →Case diameter
The approximate width of the watch case, usually measured in millimeters without the crown.
Explore related watches or advice →Lug-to-lug
The distance between the outermost ends of the watch's lugs, useful for judging how a watch may sit across the wrist.
Explore related watches or advice →Lugs
The protruding parts of the watch case where a strap or bracelet attaches.
Explore related watches or advice →Lug width
The measurement between the lugs where a replacement strap attaches, typically stated in millimeters.
Explore related watches or advice →Case thickness
The overall height of a watch case from its back to its highest point, often including the crystal.
Explore related watches or advice →Bezel
A ring around the watch crystal. Depending on the model it may be fixed, rotate, or carry a scale.
Explore related watches or advice →Unidirectional bezel
A bezel designed to rotate in only one direction, often found on dive-style watches for timing elapsed minutes.
Explore related watches or advice →Crown
The external control usually used to set time and date, and sometimes to wind a watch.
Explore related watches or advice →Screw-down crown
A crown that threads into the case to help seal it. It must be secured according to the manufacturer's instructions.
Explore related watches or advice →Caseback
The rear cover of a watch case, which may be solid or have a display window.
Explore related watches or advice →Exhibition caseback
A transparent window in the caseback that lets the wearer see some or all of the movement.
Explore related watches or advice →Sapphire crystal
A hard, scratch-resistant transparent watch cover made from synthetic sapphire. It can still chip or break after an impact.
Explore related watches or advice →Mineral crystal
A glass watch cover used across many price ranges. Its scratch and impact performance depend on the specific material and treatment.
Explore related watches or advice →Acrylic crystal
A lightweight plastic watch cover that can scratch but is often easier to polish than harder crystal types.
Explore related watches or advice →Stainless-steel case
A case made from corrosion-resistant steel alloys; the exact grade and finish can vary by watch.
Explore related watches or advice →Bracelet
A linked metal or other articulated band fitted to a watch case.
Explore related watches or advice →Deployant clasp
A hinged fastening system that folds closed to secure a watch strap or bracelet.
Explore related watches or advice →Water resistance
A rated level of protection from water exposure under specified test conditions. A rating does not guarantee safety in every activity or after seal deterioration.
Explore related watches or advice →ATM / bar
Units commonly used on watch water-resistance markings. One bar is approximately one atmosphere of pressure, not a safe diving depth instruction.
Explore related watches or advice →Dials, functions and complications
Dial
The face beneath the watch hands, usually carrying the hour markers and any subdials or calendar displays.
Explore related watches or advice →Indices
Hour or minute markers placed on the dial, which may be printed, applied or made with luminous material.
Explore related watches or advice →Lume
Luminous material applied to hands, markers or bezels to improve legibility in low light after it has been charged by light.
Explore related watches or advice →Complication
A mechanical watch function beyond basic hour, minute and seconds display, such as a date, chronograph or moonphase.
Explore related watches or advice →Chronograph
A watch function that measures elapsed time using an independently controlled timer, typically with pushers and subdials.
Explore related watches or advice →Chronometer
A watch or movement whose accuracy has been certified to a specified testing standard. It is not the same thing as a chronograph.
Explore related watches or advice →Subdial
A smaller display set within a watch dial for functions such as small seconds, elapsed minutes or a second time zone.
Explore related watches or advice →Date window
A small opening on the dial showing the current calendar date.
Explore related watches or advice →Day-date
A watch display showing both the day of the week and the date.
Explore related watches or advice →GMT watch
A watch with an additional 24-hour hand or similar mechanism to track another time zone.
Explore related watches or advice →Moonphase
A watch display that indicates the approximate current phase of the moon through a rotating disk or other mechanism.
Explore related watches or advice →Tachymeter
A scale often paired with a chronograph to calculate average speed over a known distance.
Explore related watches or advice →Telemeter
A scale that can estimate the distance to a visible and audible event using the difference between seeing and hearing it.
Explore related watches or advice →Tourbillon
A rotating carriage housing parts of a mechanical escapement, originally developed to average out some position-related timing errors.
Explore related watches or advice →Skeleton watch
A watch designed to expose substantial parts of its movement through cutouts or a transparent dial.
Explore related watches or advice →Open-heart dial
A dial opening that shows a small visible portion of the movement, often the oscillating balance wheel.
Explore related watches or advice →Buying, collecting and ownership
Reference number
The manufacturer's identifier for a specific watch version. It helps distinguish models with similar names, colors and dial configurations.
Explore related watches or advice →MSRP
Manufacturer's suggested retail price. It may differ from the actual price offered by a retailer.
Explore related watches or advice →Authorized dealer
A retailer recognized by a brand to sell its products. Warranty coverage and dealer status should be checked with the brand or seller.
Explore related watches or advice →Gray-market watch
A genuine watch sold outside a brand's authorized distribution channel. The warranty may differ from a manufacturer's authorized-dealer warranty.
Explore related watches or advice →Warranty
The written coverage describing which defects or services are eligible, for how long, and which provider is responsible.
Explore related watches or advice →Service interval
A suggested time between watch inspections or maintenance visits. The correct interval depends on movement, use and manufacturer guidance.
Explore related watches or advice →Watch servicing
Professional cleaning, inspection, adjustment and, where needed, replacement of movement parts or seals to maintain function.
Explore related watches or advice →Watch pool / group buy
A purchasing model where eligible watch commitments within one Harbor2Arbor price bracket collectively advance toward High Five, Power Ten and Lucky 13 milestones.
Explore related watches or advice →Horology
The study and practice of measuring time, including clockmaking and watchmaking.
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