Collector’s vocabulary
Watch glossary
119 terms
- Acrylic crystal
A watch’s transparent cover made from acrylic material. Seiko’s historical Queen Seiko account describes a box-shaped acrylic example. Acrylic identifies the material, while box-shaped, domed or faceted describes form; the two should be recorded separately.
Seiko · Queen Seiko, Design 140 historical collection ↗- Alpha hands
Hands with a gently tapering outline. Alpha describes their shape; it does not establish their material, age or originality to a particular watch.
Seiko · Definitions of Features: hands, PDF page 3 ↗- Anglage
Finishing the edge of a component with a smooth, polished bevel between its face and flank.
Patek Philippe · Glossary ↗- Annual calendar
A calendar that normally needs one manual correction per year, at the end of February.
Patek Philippe · Glossary ↗- Applied hour markers
Numerals or hour markers attached above the dial surface, often by riveting. Applied describes their construction; it does not identify the metal or establish the originality of a vintage dial. A maker’s use of gold for its own markers should not be assumed for other brands.
Patek Philippe · Glossary: Applique and Numeral; dial-making terminology ↗- Asthmometer
A chronograph scale that estimates breaths per minute from the time taken to count the number of complete breathing cycles marked on the dial, often five. A respiration scale measures breathing, whereas a pulsometer counts heartbeats; the dial’s stated base determines the count.
Fratello · How Watches Work: Chronograph Scales ↗- Automatic
A mechanical movement wound by a rotor as the watch moves on the wrist.
Rolex · Datejust ↗- Balance spring
The fine spiral spring that works with the balance wheel to form the movement’s oscillator.
British Watch and Clock Makers’ Guild · Glossary ↗- Barrel
The drum that contains the mainspring.
British Watch and Clock Makers’ Guild · Glossary ↗- Baton hands
Narrow, stick-shaped hands. Baton describes the outline rather than whether the hands contain luminous material or were fitted when a watch was first made.
Seiko · Definitions of Features: hands, PDF page 3 ↗- Bezel
The frame surrounding the crystal at the front of a watch.
British Watch and Clock Makers’ Guild · Glossary ↗- Bullhead
A chronograph case layout with the pushers at the top, near twelve o’clock. The term describes the control arrangement, not a particular movement. Different watches called Bullhead can have different case shapes, dials and crown positions.
Phillips · Omega ST146.011-69 catalogue essay ↗- Bumper automatic
An automatic winding system whose pivoting weight travels through a limited arc, meeting spring buffers at the ends of its swing. Wrist motion moves the weight to wind the mainspring. Unlike a full-rotation rotor, the weight cannot turn continuously through 360 degrees; the travel angle varies by design.
NAWCC · Randy Jaye, Progression of Wristwatch Styles, Part 2 (2018), p. 16 ↗- Cabochon
A stone polished into a smooth dome without facets. In watches, cabochons can decorate the crown or dial; the term describes the cut rather than a particular gemstone.
Fondation Haute Horlogerie · Cabochon ↗- Caliber
The designation of a watch movement, identifying its design or movement family.
Fondation de la Haute Horlogerie · Calibre ↗- Cam-controlled chronograph
A chronograph whose control system uses a cam to coordinate the operating levers.
Fondation de la Haute Horlogerie · Chronograph ↗- Cap jewel
An unpierced bearing stone against which the end of a movement pivot rests. Also called an endstone, it works with a separate hole jewel through which the pivot passes.
Grant Hood · Modern Methods in Horology (1904), pp. 69–70, figures 1–2 ↗- Centre seconds
A seconds hand mounted on the same axis as the hour and minute hands.
British Watch and Clock Makers’ Guild · Glossary ↗- Certificate of authenticity
A document stating an authentication assessment under the issuing organisation’s terms. Longines issues its certificate after a watchmaker’s examination and limits it to the watch’s condition when received; later component changes fall outside that assessment. It is distinct from an archive extract.
Longines · History of my watch ↗- Champlevé
Enamel decoration made by cutting recesses into a metal surface, then filling and firing enamel in those recesses.
Fondation de la Haute Horlogerie · Enameller ↗- Chapter ring
A circular scale around the dial marking divisions of time. On vintage watches, the presence or absence of a ring around the minute track can distinguish dial types.
The Metropolitan Museum of Art · European Clocks and Watches, glossary ↗Illustrative schematic; not a watch photograph.
- Chaton
A setting that holds a bearing jewel in a watch movement. In Lange’s traditional screwed gold chatons, the ruby bearing sits in a gold setting secured to the movement plate by screws. The chaton is the setting, not the jewel itself.
A. Lange & Söhne · Three-quarter plate, bearing-jewel settings ↗- Chronograph
A watch function for starting, stopping and resetting an elapsed-time measurement independently of the ordinary time display.
Fondation de la Haute Horlogerie · Chronograph ↗- Chronograph clutch
The coupling that engages or disengages the chronograph from the movement’s going train. Designs include horizontal and vertical couplings.
Fondation de la Haute Horlogerie · Chronograph ↗- Chronometer
A watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph.
Rolex · Our signature ↗- Cloisonné
Enamel decoration in which fine metal wires divide the design into cells that are filled and fired.
Fondation de la Haute Horlogerie · Enameller ↗- Column wheel
A chronograph control system that coordinates the operating levers; a cam system is an alternative construction.
Fondation de la Haute Horlogerie · Chronograph ↗- Complete calendar
A calendar displaying the day of the week, date and month. It needs manual correction after months shorter than 31 days because it does not automatically account for their different lengths. Often accompanied by a moon-phase display, which is a separate indication. Also called a full or triple calendar.
Blancpain · Our complications: Complete Calendar ↗- Dauphine hands
Broad hands that taper towards their tips, with a central facet running lengthwise. The name describes a hand style, not a particular maker or reference.
Seiko · Definitions of Features: hands, PDF page 3 ↗- Ébauche
An incomplete movement supplied for further work before it becomes a finished watch mechanism. The parts included in an ébauche have varied by period and supplier; the term does not by itself specify a complete, assembled movement.
The Naked Watchmaker · Caliber / Calibre, Berner definition ↗- Enamel
A glass-based decorative material fused to metal by firing. In traditional dial-making, powdered enamel is applied in layers and heated in a kiln. A dealer’s colour or finish description alone does not establish this construction.
Fondation de la Haute Horlogerie · Enameller ↗- Escapement
The mechanism that controls the advance of the movement’s timekeeping gear train.
British Watch and Clock Makers’ Guild · Glossary ↗- Établissage
Watch or movement production organised around assembling components supplied by specialists, followed by adjustment, fitting the dial and hands, casing and final inspection. Historically, an établisseur coordinated the suppliers and completion of the watch.
Fondation de la Haute Horlogerie · Etablissage ↗- Extract from the archives
A document transcribing a maker’s historical records for a particular watch, which may include its recorded configuration and manufacture or sale dates. Its scope depends on the maker. Longines explicitly states that its extract does not authenticate the watch or its components.
Longines · History of my watch ↗- Faceted crystal
A watch crystal shaped with distinct angled surfaces that create a dimensional, light-catching appearance. Seiko documents cut-glass designs among late-1960s and 1970s watches. The shape alone does not identify the crystal material or prove it is original to a watch.
Seiko · The vogue for colored dials and dimensional glass ↗- Feet first
Dial depth-rating text that places the feet measurement before the metres measurement, for example 660 ft = 200 m.
HODINKEE · Submariner Reference Points ↗Illustrative schematic; not a watch photograph.
- Flinqué
Translucent enamel applied over an engine-turned background so the engraved pattern remains visible beneath it.
Fondation de la Haute Horlogerie · Enameller ↗- Flyback chronograph
A chronograph whose reset pusher can be pressed during timing to return the hands to zero. A new measurement begins when the pusher is released, without a separate stop operation.
Fondation de la Haute Horlogerie · Flyback chronograph ↗- Free-sprung balance
A balance regulated by changing its inertia with adjustable weights or screws, while the balance spring’s active length remains fixed. It dispenses with the conventional index regulator that changes the spring’s working length. The term describes the regulating arrangement, not a particular hairspring material or certification.
Garrick Watchmakers · Free-Sprung Balance ↗- Fumé dial
A dial with a graduated colour finish, typically lighter at the centre and darker near the rim. Fumé describes the smoked effect; this deliberate finish differs from colour changes caused by aging.
H. Moser & Cie. · Endeavour Perpetual Calendar, Gradient Burst ↗- Fusee
A grooved, tapered pulley used to even out the mainspring’s changing pull. In a chain-and-fusee watch, a chain links it to the barrel; as the spring unwinds and its pull weakens, the chain acts at larger radii to increase leverage.
Grossmann & Grossmann · Lessons in Horology I, p. 68 (PDF page 78) ↗- Galvanic plating
An electrochemical process that deposits a layer of metal onto a conducting surface. In watchmaking it can protect movement components or change a dial’s colour. Galvanic describes a process; the term alone does not establish a dial’s age or originality.
Patek Philippe · Glossary: Galvanization and Galvanic plating ↗- Geneva stripes
A decorative finish of broad, repeated stripes on movement components such as bridges or rotors, also called Côtes de Genève. The pattern describes surface decoration; its presence alone is not a Geneva Seal or chronometer certificate.
Patek Philippe · Glossary: Geneva stripes / Côtes de Genève ↗- German silver
A copper-based alloy containing nickel and zinc, used for movement plates, bridges and cocks. The name refers to its silvery appearance rather than sterling-silver content. Lange uses it untreated, allowing its surface to develop a warm patina; this should not be confused with gold plating.
A. Lange & Söhne · German silver: aesthetically appealing and sophisticated ↗- Gilt dial
In classic vintage Rolex usage, a dial whose gold-coloured text or markings reveal the metal beneath the dark surface coating. Gold-coloured printing alone does not establish this construction.
Rolex GMT Master 1675 · Gilt Dials ↗Illustrative schematic; not a watch photograph.
- Going train
The sequence of wheels and pinions that transmits power to the escapement.
British Watch and Clock Makers’ Guild · Glossary ↗- Gold-filled case
A case made with a layer of gold alloy bonded to base metal. Gold-filled describes a layered material, rather than a case made throughout from gold alloy. The particular case’s markings and documented specifications are needed to establish its gold fineness and amount.
AWI · James Adams, Watch Cases, Horological Times (January 1988), p. 28 ↗- Grand feu
High-temperature fired enamel. The term describes the firing process; it does not identify a dial’s colour or decorative pattern.
Fondation de la Haute Horlogerie · Enameller ↗- Guilloché
Decorative patterns engraved into a surface with an engine-turning machine. Similar-looking patterns do not by themselves establish how a dial was made.
Breguet · Appearance of guilloché in watchmaking ↗- Gyromax
Patek Philippe’s adjustable-inertia balance system. Turning asymmetric weights on the balance changes its inertia to regulate the watch’s rate, in place of a conventional index regulator. The name identifies a particular system; it does not describe every free-sprung balance.
Patek Philippe · Glossary: Gyromax ↗- Hardlex
Seiko’s designation for inorganic tempered watch glass. Its crystal-parts documentation distinguishes Hardlex from acrylic and sapphire glass. A description of a vintage watch as having Hardlex does not establish that its fitted crystal is original.
Seiko · Crystal-parts coding excerpt, printed page 16 (Seiko World Time mirror) ↗- Heart cam
A heart-shaped component attached to a chronograph hand’s arbor. A reset hammer presses against its profile to return the hand to zero.
Fondation de la Haute Horlogerie · Chronograph ↗- Hole jewel
A pierced bearing stone through which a movement pivot passes. It supports the pivot at its sides; a separate cap jewel, when fitted, provides the surface against which the pivot’s end rests.
Grant Hood · Modern Methods in Horology (1904), p. 70, figure 2 ↗- Horizontal clutch
A chronograph coupling that engages toothed wheels by moving them sideways into mesh. Also called a lateral clutch. It describes the coupling, separately from the column-wheel or cam system that controls it.
Horopedia · Chronograph, horizontal coupling ↗- Independent seconds
A historical arrangement in which a central seconds hand is driven by a train separate from the hours and minutes. In the Fondation Haute Horlogerie definition, the hand advances once per second. This describes the mechanism, rather than simply a seconds display on a small subdial.
Fondation Haute Horlogerie · Independent seconds ↗- Integrated chronograph
A chronograph whose timing mechanism is built into the watch movement.
Fondation de la Haute Horlogerie · Chronograph ↗- Jewel
A natural or synthetic stone used as a bearing or endstone for a movement pivot.
British Watch and Clock Makers’ Guild · Glossary ↗- Keyless winding
Winding the mainspring through a crown and stem without a separate winding key. Keyless describes the winding arrangement; it does not mean automatic winding or by itself specify how the hands are set.
Fondation Haute Horlogerie · Jean-Adrien Philippe ↗- Ladder bracelet
A bracelet with alternating open centre links that give it a ladder-like appearance. Gay Frères designed the original Zenith version in 1969; modern reproductions also exist, so the style alone does not establish an original-period bracelet.
Zenith · Titanium Ladder Bracelet media alert, August 2024 ↗- Luminous hands
Hands containing light-emitting material, often within an opening in a metal frame. The description alone does not identify the luminous compound or establish whether it has been replaced.
Seiko · Definitions of Features: hands, PDF page 3 ↗- LumiNova and Super-LumiNova
Trade names for luminous coatings that absorb light and release it in darkness. These non-radioactive materials differ from radium- and tritium-based lume.
Fondation de la Haute Horlogerie · LumiNova ↗- Mainspring
The coiled spring that stores energy to power a mechanical watch, usually housed in a barrel.
British Watch and Clock Makers’ Guild · Glossary ↗- Maltese-cross stopwork
A form of stopwork using a finger and a notched, cross-shaped wheel to limit the barrel’s turns. A blocked sector arrests rotation at the chosen limits.
Grossmann & Grossmann · Lessons in Horology I, p. 79 (PDF page 89) ↗- Manchette
A cuff-style watch design that visually joins the case and bracelet around the wrist. Patek Philippe uses the term for the original Twenty~4, whose curved rectangular case follows the wrist; the term does not identify a movement type.
Patek Philippe · Twenty~4 history, October 2020, page 1 ↗- Manual winding
Winding a mechanical watch’s mainspring by turning the crown. Some automatic movements also allow manual winding.
Seiko · How to wind the mainspring ↗- Matte dial
A dial with a low-gloss surface finish. It describes the finish rather than a particular colour or luminous material.
HODINKEE · GMT-Master Reference Points ↗- Meters first
Dial depth-rating text that places the metres measurement before the feet measurement, for example 200 m = 660 ft.
HODINKEE · Submariner Reference Points ↗Illustrative schematic; not a watch photograph.
- Micro-rotor
A compact, off-centre oscillating weight that winds an automatic watch. Recessed into the movement rather than mounted above it, it helps reduce overall thickness. Its material, winding direction and efficiency depend on the calibre.
Piaget · Ultra-thin movements and calibre 12P ↗- Microstella
Rolex’s system of small adjustable screws or nuts on the balance wheel, used to change its inertia and regulate the watch’s rate. Introduced as screws in 1957 and developed into nuts in 1983, it allows rate adjustment with the movement still cased. The name identifies the Rolex system, rather than every adjustable-inertia balance.
Rolex · Microstella ↗- Microtor
Universal Genève’s name for its compact automatic-winding architecture with a small, off-centre oscillating weight recessed into the movement plate. A 1958 technical description explains this layout. The name is associated with the maker’s micro-rotor movements; it does not identify one particular calibre or imply that every version has the same specifications.
HIA Journal · Universal Microtor technical description (July 1958), pp. 4–5 ↗- Modular chronograph
A chronograph whose timing mechanism is an additional module mounted on a base movement.
Fondation de la Haute Horlogerie · Chronograph ↗- Monopusher chronograph
A chronograph controlled by one pusher that advances through start, stop and reset. The pusher may be integrated into the crown or separate from it. A single-pusher layout does not by itself establish a flyback function.
Longines · Monopusher Chronograph: The Origins of Precision ↗- Moon-phase display
An astronomical indication showing the Moon’s changing appearance through its cycle, averaging about 29.5 days. Display accuracy and the interval between corrections depend on the mechanism; a maker’s specification for one calibre should not be applied to every moon-phase watch.
A. Lange & Söhne · Lange 1 Moon Phase, lunar-cycle explanation ↗- Movement
The working mechanism inside a watch or clock.
British Watch and Clock Makers’ Guild · Glossary ↗- Oscillating pinion
A chronograph coupling using a movable shaft with two pinions to connect or disconnect the timing mechanism from the movement. Its role differs from the oscillating weight, which winds an automatic watch.
TAG Heuer · Everything You’ve Always Wanted To Know About TAG Heuer ↗- Panda dial
A pale chronograph dial with contrasting dark subsidiary registers. The term describes the colour arrangement; it does not establish a watch’s age, originality or reference.
Zenith · Chronomaster Original Triple Calendar press release, 29 January 2024 ↗- Perlage
A decorative finish of overlapping small circles on movement plates or bridges.
Patek Philippe · Glossary ↗- Perpetual calendar
A calendar mechanism that accounts for different month lengths and leap years.
British Watch and Clock Makers’ Guild · Glossary ↗- Pinion
A small gear in a movement, typically driven by a larger wheel.
British Watch and Clock Makers’ Guild · Glossary ↗- Power reserve indicator
A display showing the mainspring’s winding state and the corresponding remaining running time.
Grand Seiko · Power reserve indicator ↗- Pulsometer
A chronograph scale estimating heartbeats per minute from the time taken to count the number of beats specified on the dial.
Patek Philippe · Multi-Scale Chronograph technical notes ↗- Quickset date
A setting function that adjusts the date directly through a crown position, without repeatedly advancing the hands through full days.
Tudor · The chronographs: from 1976 to 1991 ↗- Radium
A radioactive element historically used in luminous paint on watch dials and hands. Its use belongs to the history of luminous materials, rather than a particular dial colour.
Fondation de la Haute Horlogerie · LumiNova ↗- Railway minute track
A minute scale whose parallel outlines and connecting marks resemble railway tracks.
Patek Philippe · Glossary ↗- Retrograde hand
A hand that travels along an arc, then jumps back to its starting point when it reaches the end.
Patek Philippe · Glossary ↗- Reverse-panda dial
A dark chronograph dial with contrasting light subsidiary registers. Reverse panda describes the colour arrangement; it does not authenticate fitted components or identify a particular reference.
TAG Heuer · Raising a glass to the TAG Heuer Carrera, 27 March 2023 ↗- Ribbon dial
In vintage Omega collector usage, a dial with repeating bands that create a ribbon- or curtain-like surface. The term covers several textured executions. A dial described as côtes de Genève is a collector comparison; it does not establish the movement-finishing process or authenticate the dial.
Omega Forums · PlainVanilla’s Seamaster special-dial guide, ribbon section ↗- Rolled gold plate
Gold alloy rolled into a thin layer and bonded to a base metal. Related to gold-filled construction, the term identifies a layered material rather than solid gold or an electroplated deposit. It does not by itself specify one universal layer thickness or gold proportion.
AWI · James Adams, Watch Cases, Horological Times (January 1988), p. 28 ↗- Rotor
An oscillating weight that uses wrist movement to wind an automatic watch’s mainspring.
Patek Philippe · Glossary ↗- Running seconds
The ordinary seconds display driven by the watch’s going train. On a chronograph, it continues to show the movement running independently of the elapsed-time seconds hand.
Fondation de la Haute Horlogerie · Chronograph ↗- Sapphire crystal
A watch glass made from transparent synthetic sapphire, valued for its resistance to scratching.
Patek Philippe · Glossary ↗- Screw-down crown
A crown secured to the case by a threaded connection, intended to improve sealing when screwed closed. It is unscrewed before winding or setting. Its presence alone does not establish a watch’s current water resistance.
OMEGA · Ultra Deep user manual, PDF pages 4 and 6 ↗- Sei Tacche
An Italian collector nickname meaning six notches, referring to the tool recesses in a screw-down caseback. The Longines 5699 is one documented example. The term alone does not identify a reference, date or present water resistance.
Longines Icons · The Longines Sommatore Centrale 13ZN-12 ↗- Seiko notch case
Collector terminology for an early Seiko 6139-600x case with a small recess exposing the crown. The notch alone does not establish a specimen’s date or originality.
Craft + Tailored · Blue Speedtimer 6139-6000 ↗- Service dial
A replacement dial fitted during servicing. Its design can differ from the dial originally supplied with the watch; a correct reference number alone does not establish an original dial.
HODINKEE · Submariner Reference Points ↗- Skeleton hands
Hands with cut-out centres that leave an open frame. This describes the hands themselves, rather than a skeletonised movement.
Seiko · Definitions of Features: hands, PDF page 3 ↗- Skeleton movement
A movement with parts of its plate and bridges opened out to reveal the mechanism while retaining the structure needed to operate. The term describes the movement’s construction; a transparent caseback alone does not make a movement skeletonised.
Fondation Haute Horlogerie · Skeleton movement ↗- Slide-rule bezel
A circular calculation scale that works with another scale on the dial or bezel. Aligning the scales allows calculations such as multiplication and division. It is a calculating tool separate from the chronograph’s elapsed-time function; the available scales and pointer arrangement depend on the watch.
Breitling · About the Navitimer: circular slide rule ↗- Slipping bridle
A spring arrangement that permits slipping at full wind to limit further tension in the mainspring. It can be used in manually wound as well as self-winding movements; its presence alone does not identify the winding type.
Patek Philippe · Ref. 5101R technical release, PDF page 1 ↗- Sommatore
A collector name associated with Longines 13ZN-12 chronographs, whose elapsed-minute counter uses a central hand alongside the chronograph seconds hand. These hands measure different units; their shared central position does not make the watch a split-seconds chronograph.
Longines Icons · The Longines Sommatore Centrale 13ZN-12 ↗- Split-seconds chronograph
A chronograph with two superimposed timing hands. One can be stopped to read an intermediate time while the other continues; releasing the stopped hand makes it catch up and run together with the other again. This allows comparison of events that start together.
Fondation de la Haute Horlogerie · Chronographe à rattrapante ↗- Spring bar
A telescoping bar used to attach a watch strap to its case.
British Watch and Clock Makers’ Guild · Glossary ↗- Spring Drive
Seiko’s mainspring-powered movement system with electronic regulation against a quartz reference. The unwinding spring drives the hands and generates the electricity used by the regulator, which controls a glide wheel through electromagnetic braking. It requires no battery and differs from both a conventional mechanical escapement and a battery-powered quartz movement.
The Seiko Museum Ginza · Spring Drive ↗- State-of-winding indicator
Patek Philippe’s indication of the winding state and when a self-winding watch should be wound. The maker distinguishes this IZR function from IRM, its abbreviation for an indication of remaining running time. For vintage references, use the terminology specified for the particular mechanism.
Patek Philippe · Glossary: IZR and IRM ↗- Stop-seconds
A time-setting function that stops the running seconds when the crown is pulled, commonly by arresting the balance in a mechanical watch. It allows synchronisation with a reference time signal. Also called hacking seconds; stopping does not itself return the hand to zero.
NOMOS Glashütte · Crown ↗- Stopwork
A mechanism that limits the mainspring’s usable winding and unwinding range, avoiding the extremes where its delivered force varies more. It arrests winding and running at preset limits.
Grossmann & Grossmann · Lessons in Horology I, pp. 78–79 (PDF pages 88–89) ↗- Tachymeter
A chronograph scale that converts the time taken to travel a known distance into average speed. The distance and scale units must correspond.
Patek Philippe · Multi-Scale Chronograph technical notes ↗- Telemeter
A scale estimating distance from the interval between seeing an event and hearing its sound, such as lightning followed by thunder.
Patek Philippe · Multi-Scale Chronograph technical notes ↗- Three-quarter plate
A large upper movement plate supporting the bearings of the going train in a single structure, rather than across several separate bridges. Its name describes its approximate coverage of the movement. Associated with Glashütte watchmaking, it leaves the balance and its supporting cock exposed.
A. Lange & Söhne · Three-quarter plate ↗- Three-star Longines marking
Three stars used in historical Longines branding: a 1922 G. Welsch advertisement places them beneath the maker’s name. That advertising use does not establish what stars signify on every later dial. A particular watch still needs its own evidence for retailer delivery, originality and any chronometer certification.
Mundial no. 101 · Longines advertisement, 21 April 1922, PDF page 2 ↗- Totaliser
A chronograph counter that accumulates elapsed minutes or hours as the chronograph seconds hand completes its revolutions.
Fondation de la Haute Horlogerie · Counter ↗- Tourbillon
A rotating cage carrying the escapement and balance, devised to average positional rate errors caused by gravity in upright pocket watches.
Fondation de la Haute Horlogerie · Tourbillon ↗- Tre Tacche
An Italian collector nickname meaning three notches, referring to the three tool recesses in a screw-down caseback. Associated with vintage Longines watches, it describes a caseback construction rather than one reference or case size. Historical water-resistance construction does not establish a vintage watch’s present water resistance.
Christie’s · Longines reference 6119, lot essay ↗- Tri-Compax
Universal Genève’s model name for a watch combining chronograph, calendar and moon-phase functions. The three refers to these complications, rather than the number of dial registers. It is not a generic name for every chronograph with three subdials.
Alpha Hands · Universal Genève 881101/01 introduction ↗- Tritium
A radioactive luminous-paint ingredient used on many vintage watches after radium. On RAF IWC Mark 11 replacement dials, an encircled T identified the tritium specification.
IWC · Pilot’s watches historical references ↗- Vertical clutch
A chronograph coupling that engages the driving and chronograph wheels along their shared axis using spring pressure. It helps avoid a jump of the chronograph hand when timing starts.
Grand Seiko · Tradition Meets Innovation: Spring Drive Chronograph ↗- Water resistance
A watch’s ability to resist water entering its case under specified conditions, often stated as a pressure or equivalent depth. Seals can deteriorate and the crown can be damaged, so an original rating does not establish a vintage watch’s present resistance.
OMEGA · Ultra Deep user manual, PDF pages 2, 4 and 6 ↗- Zero-Reset
A. Lange & Söhne’s time-setting mechanism that stops the movement and returns the seconds hand to zero when the crown is pulled. Pushing the crown home restarts the movement and seconds hand, allowing synchronisation to a time signal. Its return-to-zero action goes beyond simply stopping the seconds hand.
A. Lange & Söhne · Zero-Reset mechanism ↗- Zero-Restart
Lange’s seconds-synchronising function on the Richard Lange Referenzuhr. Pressing its pusher returns the seconds hand to zero and holds it there until release, while the watch continues running. It differs from the crown-operated Zero-Reset mechanism, which stops the movement during setting.
A. Lange & Söhne · Unforgettable masterpieces, Richard Lange Referenzuhr ↗