Watch Terminology Glossary
Navigate the world of horology with confidence. From basic terms to collector jargon.
Movement & Mechanics
Automatic (Self-Winding) A mechanical movement that winds itself using a weighted rotor that spins as you move your wrist.
Balance Wheel The oscillating wheel that regulates the release of energy in a mechanical movement. Typically beats at 28,800 bph (4 Hz).
Beats Per Hour (BPH) How many times the balance wheel oscillates per hour. Higher = smoother second hand sweep. Common: 21,600 (3 Hz), 28,800 (4 Hz), 36,000 (5 Hz).
Caliber (or Calibre) The specific movement model. Example: Rolex Caliber 3235, Omega Caliber 8800.
Chronometer A watch certified for accuracy by COSC (Swiss Official Chronometer Testing Institute). Must be within -4/+6 seconds per day.
Co-Axial Escapement Omega’s proprietary escapement design that reduces friction, extending service intervals and improving long-term accuracy.
Complication Any function beyond displaying hours, minutes, and seconds. Examples: date, chronograph, moon phase, GMT.
Escapement The mechanism that controls the release of energy from the mainspring to the balance wheel. Creates the “tick-tock” sound.
Frequency Rate of balance wheel oscillation, measured in Hertz (Hz) or beats per hour (bph). Higher frequency = better accuracy potential.
Jewels Synthetic rubies used as low-friction bearings in the movement. More jewels doesn’t necessarily = better, but 17+ is standard for quality watches.
Mainspring The coiled spring that stores energy in a mechanical watch. Winding the watch tensions this spring.
Mechanical Movement A watch powered by a wound mainspring (no battery). Either hand-wound or automatic.
Power Reserve How long a mechanical watch runs on a full wind. Typical: 38-48 hours. Long reserve: 70-80 hours. Exceptional: 7-10 days.
Quartz Movement A battery-powered movement using a quartz crystal oscillator. Much more accurate than mechanical (±10-15 seconds/year vs. ±5-15 seconds/day).
Regulation Adjusting the watch to run faster or slower for accuracy. Done by watchmaker.
Rotor The weighted semi-circular component in an automatic movement that spins to wind the mainspring.
Spring Drive Seiko’s hybrid movement: mechanical mainspring + quartz regulation. Accuracy: ±1 second/day. Perfectly gliding second hand.
Complications
Annual Calendar Automatically adjusts for months with 30 or 31 days. Requires manual correction once per year (February).
Chronograph A stopwatch function. Operated by pushers, displays elapsed time on sub-dials.
Date (Big Date) Displays the date with two separate discs for tens and ones digits, creating a larger, more legible date.
Day-Date Displays both day of the week and date.
GMT (Greenwich Mean Time) A second hour hand for tracking an additional timezone. True GMT has independently adjustable hour hand.
Moon Phase Displays the current phase of the moon through an aperture.
Perpetual Calendar Automatically accounts for months of different lengths AND leap years. Requires no adjustment if kept running.
Power Reserve Indicator Displays how much power remains in the mainspring (like a fuel gauge).
Rattrapante (Split-Seconds Chronograph) A chronograph with two second hands for timing multiple events simultaneously or lap times.
Tourbillon A rotating cage containing the escapement and balance wheel, designed to counter the effects of gravity on accuracy. Mostly decorative in wristwatches.
World Timer Displays time in multiple (usually 24) time zones simultaneously.
Case & Construction
Bezel The ring surrounding the watch crystal. Can be fixed, rotating (dive watches), or decorative.
Case The metal housing that protects the movement.
Caseback The rear cover of the case. Can be solid, transparent (exhibition), or engraved.
Crown The knob used to wind the watch and set the time/date.
Crystal The transparent cover protecting the dial. Types: acrylic (plastic, polishable), mineral (glass), sapphire (scratch-resistant).
Exhibition Caseback A transparent caseback (usually sapphire) that allows viewing of the movement.
Integrated Bracelet A bracelet design where the links flow seamlessly from the case (no distinct separation). Examples: Audemars Piguet Royal Oak, Patek Philippe Nautilus.
Lug Width The distance between lugs where the strap attaches. Common: 18mm, 20mm, 22mm.
Lugs The protruding parts of the case where the strap or bracelet attaches.
Pushers Buttons on the case used to operate complications (chronograph start/stop/reset).
Screw-Down Crown A crown that screws into the case for better water resistance.
Unidirectional Bezel A bezel that only rotates counterclockwise, used on dive watches to measure elapsed time safely.
Dial & Hands
Applied Indices (Applied Markers) Hour markers that are separately made and attached to the dial (vs. printed). Adds depth and luxury.
Dial The face of the watch displaying the time and complications.
Guilloche A decorative engraving pattern on the dial, created by engine-turning. Classic watchmaking technique.
Hands The pointers indicating hours, minutes, and seconds.
Indices (Markers) The hour markers on the dial. Can be Arabic numerals, Roman numerals, batons, or dots.
Lume (Luminous Material) Phosphorescent material on hands and markers that glows in the dark. Modern: Super-LumiNova. Vintage: radium (radioactive, no longer used), tritium.
Sub-Dial Smaller dials within the main dial, often for chronograph or date functions.
Sunburst A dial finish that radiates from the center, creating a dynamic light effect.
Straps & Bracelets
Bracelet A metal strap integrated with or matched to the watch case.
Deployment Clasp (Deployant) A folding clasp that opens without removing the strap from wrist. Reduces wear on leather.
Jubilee Bracelet Rolex’s five-link metal bracelet design (vs. three-link Oyster).
Leather Strap Traditional strap material. Types: calfskin, alligator, crocodile, ostrich.
Micro-Adjustment Small adjustments available on some clasps for fine-tuning bracelet fit (typically 2mm increments).
NATO Strap One-piece nylon strap that passes under the watch case. Originally military (British Ministry of Defence).
Oyster Bracelet Rolex’s three-link metal bracelet design. Robust and sporty.
Rubber Strap Modern alternative to leather for sports watches. Durable, waterproof, comfortable.
Spring Bar The small metal pin that holds straps to the case lugs.
Water Resistance
30m (3 ATM) Splash resistant. NOT suitable for swimming.
50m (5 ATM) Light swimming okay. No diving.
100m (10 ATM) Swimming and snorkeling suitable.
200m (20 ATM) Scuba diving suitable. True dive watch starts here.
300m+ (30+ ATM) Professional diving. Exceeds most recreational diving needs.
ATM (Atmospheres) Unit of pressure. 1 ATM = ~10 meters depth.
Water Resistance The watch’s ability to resist water ingress. NOT the depth you can dive to (static test, not dynamic real-world use).
Finishing & Decoration
Anglage Beveling and polishing the edges of movement components. Sign of high-end finishing.
Black Polish (Mirror Polish) The highest level of polishing, creating a deep reflective surface. Extremely labor-intensive.
Brushed Finish A textured finish with fine parallel lines, created by brushing metal surface.
Côtes de Genève (Geneva Stripes) Decorative wave pattern on movement plates. Traditional Swiss finishing.
Perlage (Circular Graining) Decorative circular overlapping pattern on movement plates.
PVD (Physical Vapor Deposition) A coating process for adding color/durability to cases (black, gold, etc.).
Snailing Decorative spiral pattern, often on winding rotors or sub-dial counters.
Sunray Finish Radiating brush pattern on dials, creating dynamic light play.
Zaratsu Polishing Grand Seiko’s proprietary polishing technique creating distortion-free mirror surfaces.
Watch Types
Beater A durable, inexpensive watch worn during rough activities without worry.
Chronograph A watch with stopwatch function.
Dive Watch A watch designed for underwater use. Must have: unidirectional bezel, luminous markers, 200m+ WR.
Dress Watch A thin, elegant watch designed for formal occasions. Typically <10mm thick, simple time-only or date.
Field Watch Military-inspired watch with high legibility, durability, and simple design.
GADA (Go Anywhere, Do Anything) A versatile watch suitable for all occasions (sports-elegant hybrid).
GMT Watch A watch displaying a second time zone.
Grail Your ultimate dream watch. The one you’re saving for.
Pilot Watch (Flieger) Aviation-inspired watch with large, legible dial and typically 40mm+.
Sports Watch A robust watch suitable for active wear. Typically 100m+ WR, metal bracelet.
Tool Watch A watch designed for specific professional use (diving, aviation, racing). Function over form.
Industry Terms
AD (Authorized Dealer) Official retailer authorized by the brand to sell their watches. Provides full warranty.
COSC (Contrôle Officiel Suisse des Chronomètres) Swiss Official Chronometer Testing Institute. Certifies watch accuracy.
Gray Market Watches sold by unauthorized dealers (not fake, but no manufacturer warranty). Often discounted.
Holy Trinity The three most prestigious watch brands: Patek Philippe, Audemars Piguet, Vacheron Constantin.
Homage Watch A watch inspired by another watch’s design without being a counterfeit. Legal but often controversial.
In-House Movement A movement designed and manufactured by the watch brand itself (vs. buying from ETA, Sellita, etc.).
Manufacture A watch brand that designs and produces its own movements in-house.
METAS (Swiss Federal Institute of Metrology) Testing institute. METAS certification = resistant to 15,000 gauss magnetism + accuracy within 0/+5 seconds/day.
Microbrand Small independent watch brand, often online-only. Quality varies widely.
NOS (New Old Stock) An old watch that was never worn/sold, still in original unworn condition.
Patina Age-related changes to watch appearance (faded lume, tropical dial). Highly valued in vintage watches.
Reference Number The specific model identifier. Example: Rolex Submariner 124060.
Replica/Fake Counterfeit watch. Avoid at all costs.
Waiting List List at AD for popular models (Rolex sports, Patek Nautilus). Can be months to years.
Collector Jargon
Flipping Buying a watch to immediately resell for profit. Frowned upon by many collectors.
Honeymoon Period The first few weeks/months of owning a new watch when excitement is highest.
Inverted 6 A dial defect where the “6” in “Superlative Chronometer” on vintage Rolexes is upside-down. Now valuable variant.
Lollipop Hand A hand design with a circular tip (resembles a lollipop). Common on vintage watches and Omega Seamaster.
Mercedes Hand The iconic hour hand design on Rolex Submariners and many dive watches.
Mint Condition Perfect unworn condition, as if from factory.
Nato Spec Original 1970s British military watch specifications.
Safe Queen A watch kept unworn in a safe, never used. Generally discouraged—watches are meant to be worn!
Strap Monster A watch that looks great on many different strap styles.
Tropical Dial A dial that has faded/changed color due to UV exposure. Highly desirable in vintage Rolexes and other vintage watches.
Wrist Check Posting a photo of the watch you’re wearing (common on social media/forums).
Wrist Shot A photo of a watch on the wrist (vs. table/studio shot).
Abbreviations
AD: Authorized Dealer AP: Audemars Piguet BPH: Beats Per Hour COSC: Contrôle Officiel Suisse des Chronomètres ETA: Ebauches SA (Swiss movement manufacturer) GADA: Go Anywhere, Do Anything GMT: Greenwich Mean Time GS: Grand Seiko JLC: Jaeger-LeCoultre L2L: Lug-to-Lug METAS: Swiss Federal Institute of Metrology NOS: New Old Stock OEM: Original Equipment Manufacturer PP: Patek Philippe PR: Power Reserve PVD: Physical Vapor Deposition VC: Vacheron Constantin WR: Water Resistance
Using This Glossary
Start here if:
- Reading watch reviews and feeling lost
- Shopping and confused by descriptions
- Joining watch communities and don’t understand slang
- Want to sound knowledgeable at ADs
Bookmark and reference as you encounter new terms.
No one knows everything! Even seasoned collectors Google terms regularly.
Next Steps
- Quickstart Guide - Put these terms in context
- Understanding Movements - Deep dive into technical terms
- Watch Brands - Learn brand-specific terminology