Watch Glossary: Essential Terms & Definitions
From chronograph to tourbillon, understanding watch terminology helps you compare models, service your timepiece, and buy with confidence. This glossary from The 1916 Company defines the key watch terms to know in clear, collector-friendly language. Whether you are looking for new watches, pre-owned watches, or the latest technical innovations, use this guide to navigate the world of luxury watches with confidence.
Types of Watch Movements
Mechanical — Hand-Wound (Manual)
Powered by a mainspring that you wind via the crown. No battery. Favored for the tactile connection and traditional watchmaking.
Mechanical — Automatic (Self-Winding)
Winds itself as a rotor swings with wrist motion. Occasional manual winding can extend power reserve. If unworn, you can manually wind an automatic watch to start it — typically ~30–40 turns.
Quartz
Battery-powered movement regulated by a quartz crystal oscillator. Highly accurate and low maintenance. See also: EOL (End of Life) indicator.
Solar / Light-Powered
Quartz movement with a light-charging cell beneath the dial — reduces battery replacements.
Kinetic / Auto-Quartz
Hybrid system that uses wrist motion to charge a capacitor which powers a quartz regulator.
Spring Drive
Hybrid mechanical system made popular by Grand Seiko with a mainspring and a glide wheel regulated by a quartz reference for smooth, continuous seconds.
Radio-Controlled / GPS
Quartz watches that synchronize time via radio signals or GPS for atomic-level accuracy.
Core Watch Anatomy & Movement
Amplitude
The angle of swing of the balance wheel, often used to assess movement health during service.
Balance Spring (Hairspring)
The fine spiral spring that returns the balance wheel to center, regulating timekeeping. Learn more about how De Bethune reimagines the balance spring and explore De Bethune watches. See also: Breguet Overcoil, Free-Sprung Balance.
Balance Wheel
The oscillating wheel that divides time into equal beats — the beating heart of a mechanical watch.
Barrel
A drum housing the mainspring. Multiple barrels can increase power reserve.
Beat Rate / Frequency
The speed of the movement, typically measured in vibrations per hour (vph) or hertz (Hz) — e.g., 28,800 vph (4 Hz).
Beat Error
The difference in timing between the tick and the tock. Excessive beat error can reduce accuracy and indicates a need for regulation.
Breguet Overcoil
A hairspring with an upturned outer curve to improve isochronism and positional stability.
Bridge
A fixed frame inside the movement that supports wheels and components. See also: Skeleton Watch.
Calibre (Caliber)
The specific model of a movement, indicating its design and technical lineage. See also: Types of Watch Movements.
Co-Axial Escapement
An escapement design, made famous by Omega, that reduces sliding friction versus the Swiss lever, aiding long-term stability and service intervals.
Complication
Any function beyond time-only — e.g., chronograph, calendar, GMT, moonphase.
Escapement
The regulating mechanism that meters energy from the mainspring to the balance wheel in timed impulses.
Escape Wheel
The toothed wheel controlled by the pallet fork in the escapement.
Free-Sprung Balance
A balance without a conventional regulator index; timing is adjusted by variable inertia screws on the balance rim for robustness.
Gear Train
The series of gears that transmits energy from the barrel to the escapement and hands.
Hacking Seconds
Also called “stop seconds” — pulling the crown stops the seconds hand for precise setting.
Hairspring
See Balance Spring. Learn more about how H. Moser & Cie. redeveloped cylindrical hairsprings with a modern twist in our feature.
Incabloc / Shock Protection
Shock-absorbing settings that protect delicate pivots of the balance in case of impact.
Jewels
Synthetic rubies used as low-friction bearings at key pivot points. Typical counts range from 17+ depending on complications. Learn more about jewels in watches.
Mainspring
The coiled spring that stores energy when wound, powering the watch as it unwinds.
Micro-Rotor
A smaller rotor integrated into the movement’s plate, allowing thinner automatic watches.
Movement Holder / Movement Ring
The spacer that secures the movement inside the case for alignment and stability.
Pallet Fork
The lever in a Swiss lever escapement that alternately locks and unlocks the escape wheel while giving impulses to the balance.
Power Reserve
The running time on a full wind (e.g., 42h, 70h). Sometimes displayed via a Power Reserve Indicator.
Power Reserve Indicator
A sub-dial or aperture showing remaining energy in the mainspring.
Regulator Index
A movable index that alters the effective length of the hairspring to fine-tune rate — contrast with free-sprung balances.
Rotor
A semi-circular weight that swings with wrist motion to wind an automatic movement.
Time-Only
A watch with hours, minutes (and usually seconds) but no additional complications.
Timekeeping Complications & Functions
Alarm
An on-wrist reminder that chimes or vibrates at a set time.
Altimeter
Displays altitude above sea level for outdoor and aviation use.
AM/PM Indicator (Day-Night)
Shows whether it’s before or after midday — helpful when setting dual-time or world-time watches.
Annual Calendar
Adjusts automatically for 30/31-day months, requiring correction only at the end of February. Explore annual calendar watches.
Big Date
A large, highly legible date display, often using two separate disks.
Calendar (Day/Date)
Displays date — sometimes day and month. See also: Perpetual Calendar, Annual Calendar.
Chronograph
A stopwatch function integrated into the watch — typically with a central seconds hand and sub-dials for elapsed minutes/hours. Variants include Flyback, Rattrapante, Monopusher. See also: Tachymeter. Explore chronograph watches.
Countdown Timer
Counts down from a preset interval; common on regatta or pilot watches.
Diving Watch
Water-resistant tool watch — generally 200 m or more — with a unidirectional bezel and luminescent indices/hands for underwater use. Learn more in our dive watch guide and explore pre-owned divers.
Dual Time / GMT
Displays local time plus a second time zone — popular among frequent travelers.
Equation of Time
Shows the difference between mean solar time (civil time) and true solar time. Learn more about the Jules Audemars Equation of Time.
Flyback Chronograph
Allows instant reset and restart with one press — useful for sequential timing.
GMT (Greenwich Mean Time)
Another name for dual-time watches tracking multiple time zones. Grand Seiko is known for precise GMTs. See pre-owned GMT watches.
Grand Sonnerie
Automatically chimes hours and quarters; among the most complex and prestigious chiming mechanisms.
Jumping Hour
Digital hour display that “jumps” each hour, often paired with a minutes hand.
Minute Repeater
Chimes hours, quarters, and minutes on demand using gongs and hammers.
Monopusher Chronograph
All chronograph functions — start, stop, reset — operated via a single pusher.
Moonphase
Displays the current phase of the moon — typically a 29.5-day cycle.
Perpetual Calendar
Automatically accounts for varying month lengths and leap years with no adjustment until 2100. Patek Philippe perpetual calendars are exemplary.
Power Reserve (Complication)
A display indicating energy remaining in the mainspring.
Rattrapante (Split-Seconds)
Two central seconds hands let you time intermediate laps while the main hand continues; the split hand “catches up” when released.
Regatta Timer
A countdown, often color-coded, for yacht-race starts.
Slide Rule (Navigation Bezel)
A logarithmic scale on the bezel or dial for fuel, speed, distance, or unit conversion — common on pilot chronographs. Learn more about how to read a Breitling Slide Rule Bezel.
Sonnerie
A clock-like strike that automatically chimes hours — sometimes quarters; a Grand Sonnerie adds more functions.
Tourbillon
A rotating cage for the balance and escapement to average out gravitational errors. Explore tourbillon watches and the origins of the tourbillon.
World Time
Displays time in 24 cities/zones via a rotating city ring and 24-hour disk.
Case & Construction
Anti-Magnetic
Protection against magnetic fields that can disturb the hairspring. Some watches use soft-iron shields or non-ferrous components. Learn more about how anti-magnetic watches work.
Anti-Reflective (AR) Coating
Transparent coating on the crystal to reduce glare and improve legibility.
Case
The housing that protects the movement — typically steel, titanium, ceramic, precious metals, or composites.
Caseback
The rear cover of the case, either solid or transparent. See also: Exhibition Case Back.
Case Dimensions
Key measurements include diameter, lug-to-lug, thickness, and lug width.
Case Diameter
Width across the case, usually excluding the crown. Comfort depends on lug-to-lug and wrist size.
Ceramic
Scratch-resistant, lightweight material used for bezels and cases; can be matte or glossy.
Chamfer / Bevel
Angled polish along case edges or bridges, prized as a finishing detail.
Crown
The knob used to set the time, wind the mainspring, or adjust date/day. Variants include screw-down crowns for added water resistance.
Crystal
The transparent cover over the dial — usually sapphire (hardest), mineral, or acrylic (warm look, easily polished).
Exhibition Case Back
A transparent caseback — usually sapphire — revealing the movement.
Gasket
Rubber or polymer seals in the case, crown, pushers, and caseback to maintain water resistance.
Gold Plating
A thin layer of gold applied via electroplating; thickness measured in microns. May show wear over time.
Helium Escape Valve
A pressure-relief valve on professional dive watches to release helium during saturation diving decompression.
Lug
Case protrusions where the strap/bracelet attaches. Shape and length affect how a watch wears.
Lug-to-Lug
The distance from the tip of the top lug to the tip of the bottom lug — critical for fit.
Lug Width
The inner distance between lugs in millimeters (e.g., 20 mm) that determines strap size.
Monobloc Case
A case milled from a single block, sometimes with front-loading movements for rigidity.
Screw-Down Crown
A crown that threads into the case for improved water resistance and security.
Thickness
The height of the watch measured from caseback to crystal apex.
Water Resistance
Indicated in meters, ATM, or bar. Ratings reflect lab tests; seals should be checked during service. See also: Diving Watch.
Display, Style & Dial Details
Analog/Digital (Ana-Digi)
Hybrid display combining hands with a digital readout.
Analogue (Analog)
Traditional display using hands and a dial rather than a purely digital readout — the classic analogue watch definition.
Aperture
A window on the dial that shows a function such as date, day, or moonphase.
Applied Indices
Hour markers affixed to the dial (rather than printed), often faceted for light play.
California Dial
Dial with mixed Roman numerals (top) and Arabic numerals (bottom), often with markers at 3/9 and a triangle at 12. Panerai is well known for its California Dials.
Chapter Ring
A ring at the edge of the dial that carries minute/second markings — sometimes called the minute track.
Fumé / Gradient Dial
A dial that transitions from light center to darker edge for depth and drama. Moser is well known for their Fumé dials.
Guilloché
A decorative engraving technique that creates intricate, repeating patterns — often on dials, rotors, or casebacks. Traditionally done by hand using a rose-engine lathe; brands like Breguet are renowned for this detail.
Index / Indices
Markers on the dial indicating hours (and sometimes minutes/seconds) — can be printed, applied, or lumed. Common search intent: “watch indices meaning.” Learn more about different types of numeral indices.
Luminescence (“Lume”)
Coating on dial indices and hands (often Super-LumiNova) that glows in the dark for low-light readability.
Openworked / Skeletonized
Design that reveals movement components by removing sections of the dial/bridges. Explore skeleton dial watches and learn the subtle differences.
Sandwich Dial
Two-layer dial where cut-outs in the top layer reveal a lumed layer beneath — known for strong night legibility.
Sunburst Finish
Radial brushing that plays with light as the dial moves.
External Components
Bezel
The ring around the crystal — can rotate (uni/bi-directional) or be fixed (e.g., tachymeter). Common question: “what is a watch bezel?”
Bi-Directional Bezel
A rotating bezel that turns both clockwise and counter-clockwise — often for dual-time conversions.
Bracelet
A strap made of metal links — adjusted by adding/removing pieces.
Cambered Crystal
A domed or curved crystal that enhances legibility and vintage character.
Deployment / Deployant Buckle
A folding clasp that lets a strap or bracelet open/close securely, preserving material and improving fit.
Dial
The face of the watch with indices, numerals, and hands; may include sub-dials for complications like chronograph or power reserve.
End Links
The end pieces that connect the bracelet to the case between the lugs; solid end links improve solidity.
Pusher
A button on the case used to operate complications such as a chronograph, calendar, or GMT reset.
Rehaut / Inner Bezel
The sloped inner ring between the dial and crystal; can carry minute tracks or branding/serial engravings.
Uni-Directional Bezel
Rotates only counter-clockwise — standard for diving watches to safely track elapsed time. Learn more in our dive watch guide.
Scales, Tracks & Measuring
Minute Track / Railroad Track
A ring of minute/second hash marks used for precise reading — often on the chapter ring or rehaut.
Pulsometer
A scale that lets you measure heart rate by timing a set number of beats on a chronograph.
Tachymeter
A scale on the bezel or dial for measuring speed over a known distance — most often found on chronograph watches.
Telemeter
A scale that calculates distance to an event (like lightning) by timing the interval between seeing it and hearing it.
Quality, Standards & Authentication
Chronometer
A movement certified for accuracy by COSC (–4/+6 sec/day mechanical; ±0.2 sec/day quartz). Note: chronometer ≠ chronograph.
Geneva Seal
A hallmark certifying finishing and origin standards for movements made in the Canton of Geneva.
Gray Market
Sale of authentic watches through unauthorized dealers. Often lacks manufacturer warranties/support. Buying from trusted, authorized retailers ensures service and authenticity.
METAS / Master Chronometer
Swiss certification for accuracy, anti-magnetism, and performance in daily-wear conditions, conducted after COSC in many cases. Learn more about METAS.
Swiss Made
Legally protected designation. To qualify, at least 60% of production costs must be Swiss-based, the movement must be Swiss, and final inspection must occur in Switzerland.
Measuring, Fit & Sizing
Bracelet Sizing
Adjust by adding/removing links; micro-adjust clasps allow fine tuning. See also: End Links, Deployant Buckle.
How to Measure Your Wrist for Watch Size
Wrap a soft tape around your wrist where the watch sits. Use the lug-to-lug and case diameter to determine comfort. Common intent: “how to measure wrist for watch size.”
Strap Taper
The reduction in width from lugs to buckle — e.g., 20 mm to 16 mm — which affects comfort and look.
Care, Tools & Servicing
Authorized Service / Factory Service
Manufacturer-approved service that follows brand specifications for parts, testing, and water-resistance checks.
Caseback Opener
Tool used to remove screw-down or snap-on casebacks — for professionals, as it may affect water resistance.
Demagnetizer
Device used to remove magnetism that can cause a watch to run fast/slow.
EOL (End of Life)
A battery indicator feature on quartz watches — the seconds hand may jump every 4 seconds to signal a needed replacement.
Pressure Test / Water-Resistance Test
Test performed after service to verify water-resistance integrity to the rated depth.
Spring Bar Tool
Forked tool for removing straps/bracelets by compressing spring bars between the lugs.
Watch Press
Bench tool for pressing crystals or snap casebacks — often referenced by users searching “what is a watch press?”
Watch Winder
A motorized device that rotates an automatic watch to keep the mainspring wound when not worn. Read our watch winder guide.
Collecting & Culture
Boutique Edition
A model produced exclusively for a brand’s boutique(s) rather than multi-brand authorized retailers — often with unique design elements or engravings.
Box and Papers
Original packaging and documentation (manual, warranty card, certificate). “Full set” examples often command a premium.
Collector’s Piece
A watch valued for design, provenance, brand significance, rarity, or technical achievement — including limited editions and milestone models.
Discontinued Model
A reference or collection no longer produced. Discontinued pieces may appreciate depending on rarity and demand.
Full Set
Industry shorthand for a pre-owned watch that includes its original box, papers, and accessories.
Horology
The art and science of measuring time — encompassing watchmaking, clockmaking, and the study of timekeeping technology and history.
Limited Edition
A watch released in restricted quantity, often numbered and accompanied by certificates of authenticity.
Provenance
The documented history of a watch’s ownership, servicing, and origin, which can significantly affect value and desirability.
Quick Shortcuts
- Types of watch movements
- Watch indices meaning
- How to measure wrist for watch size
- Chronograph (stopwatch function)
- Diving watch features