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Watch Glossary

1104 horological terms explained · 15/19

Ratcheting claspClasp

Clasp with teeth that engage incrementally for precise tension control

RateTimekeeping

The measure of how many seconds per day a watch gains or loses.

Rate StabilityPrecision

Consistency of watch rate over time without external adjustment.

Rate VariationPrecision

Difference in watch rate between various positions and conditions.

RattrapanteComplications

Split-seconds chronograph with two independent stopwatch hands that can be separated and recombined.

Rattrapante ChronographComplications

Split-seconds chronograph where the second hand can be stopped independently to measure intermediate times.

Rectangular caseCase

Four-sided case with right angles and straight edges, elongated horizontally or vertically.

Red SubmarinerHistory

Vintage Submariner with red text dial printing, collectible early reference variant.

Reduction RatioMovement

Proportion of gear teeth determining speed reduction between successive gear stages

Reference NumberCollecting and Market

Model designation assigned by manufacturer identifying specific watch variant and specifications

Regatta TimerComplications

Chronograph with countdown mechanism and acoustic signal for yacht race starting procedures.

RegulatingService

Adjusting watch movement accuracy to achieve correct timekeeping performance

RegulationAdjustment

Adjustment of hairspring or balance wheel to modify watch rate.

RegulatorWatch Types

Watch with separate subdials for hours, minutes, and seconds for precise timekeeping.

Regulator indexHistory

Adjustable pointer that alters effective length of balance spring to regulate rate

RehautDial

Circular engraved area between dial edge and case inner bezel.

Rehaut lumeMaterials

Luminous coating sometimes applied to the watch rehaut ring near the dial edge

Relume serviceMaterials

Professional restoration service applying new luminous material to vintage watch dials and hands

RemontoirMovement

Intermediate wheel system providing constant force and regulating energy from the mainspring.

RepeaterComplications

Complicated watch striking hours, quarters, or minutes audibly when activated by pusher.

Replacement PartsCollecting and Market

Non-original components installed during service or repair, noted by collectors for authenticity

Reservoir Dial AnimationDial

Dynamic e-ink dial elements that update synchronously with hybrid watch mechanics

Resonance ComplicationComplications

Two balance wheels oscillating together to improve stability and accuracy through mutual synchronization.

Resonance SpringComplications

Paired balance wheels vibrating in resonance to improve chronometric stability and precision.

RetrogradeComplications

Complication with hand sweeping across arc then jumping back to start, indicating time passage.

Retrograde DisplayComplications

Hand jumps back to start position instead of rotating continuously, creating dramatic visual effect.

Reverse PandaAesthetics

Watch dial with black background and white subdials, opposite of traditional panda.

ReversoModel

Jaeger-LeCoultre's art deco rectangular flipping case watch from 1931

Rhodium PlatingSurface Coating

Applying thin rhodium coating for bright, reflective finish and improved corrosion resistance.

Ringlock SystemCase

Case design sealing crystal, case, and back for exceptional water resistance.

RivetBracelet

Metal pin permanently securing links together in a bracelet.

Rolex Caliber 3135Movement

Perpetual rotor, Parachrom hairspring, 48-hour power reserve, widely used in sports watches

Rolex Caliber 3235Movement

Evolved 3135 with Chronergy escapement, 70-hour power reserve, improved efficiency

Rolex Caliber 3285Movement

GMT-Master II exclusive, dual time module, 70-hour reserve, Chronergy escapement

Roman NumeralsDial

Classical Roman numeral hour markers for elegant formal appearance

Root Beer GMTHistory

GMT-Master II with brown and black bezel insert, resembling root beer coloring.

Rotating BezelCase

Bezel that rotates in one or both directions for timing purposes.

Rotating Timing BezelBezel

Bidirectional bezel allowing divers to track bottom time and decompression stops.

RotorMovement

Weighted oscillating component in automatic watches that winds the mainspring via wrist motion.

Roulette DateDial

Date wheel with alternating Arabic numerals and dashes creating a segmented appearance

Royal OakModel

Audemars Piguet's iconic octagonal sports watch introduced in 1972

Rubber BraceletBracelet

Sporty bracelet made from synthetic rubber, water-resistant and flexible

Rubber FKMStrap

FKM fluorocarbon rubber strap, chemical-resistant, durable, sporty aesthetic

Rubber Steel HybridBracelet

Bracelet combining rubber inserts with steel links for comfort and durability

Rubber StrapMaterials

Durable elastomer material for watch bracelets, popular in diving and sport watches

Rust PreventionMaintenance

Application of protective coatings and maintenance to prevent oxidation of components

RutheniumPlating

Dark grey precious metal plating offering distinct color and hardness

Ruthenium PlatingTreatments

Dark metallic coating providing contrast and protection to white metal watch components.

Safety StopDiving

Brief decompression hold near surface; allows final off-gassing before surfacing.

Saffiano LeatherStrap

Cross-hatched textured leather, scratch-resistant, popularized by Prada luxury goods

Sailcloth StrapStrap

Woven fabric strap traditionally used in sailing, water-resistant and durable

Sailor's ChronographComplications

Chronograph optimized for maritime use with specific timing functions for nautical operations.

Salmon dialAesthetics

Peachy-orange colored dial found on vintage Rolex models, prized by collectors.

Sandblasted BezelBezel

Bezel with fine matte texture created through sandblasting process for sophisticated appearance

Sandblasted FinishTreatments

Rough textured surface created by abrasive blasting, offering anti-reflective and aesthetic qualities.

SandblastingSurface Finishing

Abrasive blasting process using sand particles to create textured matte finishes on watches.

Sandwich caseCase

Case design with applied dial elements creating a layered appearance, often seen in military watches.

Sandwich dialMaterials

Dial construction with luminous layer between transparent sapphire and dial base for enhanced lume

Sans-serif dialAesthetics

Modern watch dial using sans-serif font for cleaner, contemporary appearance.

SantosModel

Cartier's first wristwatch designed for aviator Santos-Dumont in 1904