Watch Glossary
1676 horological terms explained
Official document certifying watch meets specified precision standards.
Official document proving watch movement meets chronometer precision standards
Forensic evaluation of inscription cut-depth, tool marks, and letter spacing for period authenticity verification.
Official COSC certification grade indicating movement precision within specific tolerances
Set of rigorous testing criteria ensuring exceptional timekeeping precision.
Degree to which watch maintains precise and consistent timekeeping.
Contrôle Officiel Suisse des Chronomètres - Swiss official chronometer testing institute
Chronometer standard: -4 to +6 seconds per day maximum variation.
Extreme altitude testing verifying chronometer performance stability
Maximum allowable variation from mean daily rate per standards.
Quality assurance procedure verifying eccentric gear dimensional accuracy pre-grinding
Auction house assessment of finishing quality and assembly precision.
Quality control parameter ensuring uniform cutting angles across matched gemstones.
Testing protocol evaluating stone adhesion and mechanical durability in watch environment.
German military certification for precision timekeeping from Gesellschaft für Strahlenforschung.
German precision watchmaking standard for military chronometers requiring ±15 seconds monthly rate.
German military acceptance testing procedure verifying chronometer-grade accuracy standards.
German military chronometer certificate documenting daily rate, amplitude, and beat error measurements.
German military (Bundeswehr) timekeeping and precision standards for issued timepieces.
Official Swiss quality certification for watches made in Geneva region
International standard for diver's watches quality, water resistance, and safety requirements
Geneva Hallmark certification applied to JLC movements, guaranteeing Swiss manufacture and quality standards.
Inspection procedure confirming eccentric gear tooth geometry matches equation curve
METAS certification for watches exceeding traditional chronometer standards
Swiss federal metrology institute certifying ultra-precision chronometer watches
Military specification requiring maximum ±20 seconds per day chronometric performance.
Military specification drop and impact testing protocol ensuring field durability.
Complete technical file proving watch meets all required military specification standards.
Specific depth rating mandated by military specification for operational field conditions.
Original U.S. military watch specification from 1940s defining ruggedness and reliability standards.
U.S. military specification for general-purpose military wristwatches issued 1968-1990.
U.S. military specification for general-purpose military wristwatches issued 1974-1990s.
US military specification for general-purpose mechanical wristwatches issued 1974-1990s.
Document issued confirming watch meets military specification requirements upon delivery.
Documentation recording all testing and inspection performed during military procurement.
Serial number system linking military watches to issuance records via MOD and NATO database archives.
MIL-W requirement for minimum submersion depth capability, typically 100m for combat use.
Hallmark or stamped symbol indicating UK Ministry of Defence approval and acceptance.
Rigorous testing protocol required for watches submitted for British military service designation.
United Kingdom Ministry of Defence requirements for serviceable military timepieces.
Official documentation proving watch passed British Ministry of Defence acceptance testing criteria.
Official verification that watch movement meets specific Swiss quality and precision standards
System indexing military timepieces by function, issuing nation, and technical specifications for logistics.
NATO Reference Number (NRN) cataloging system for military equipment including issued wristwatches.
Omega's advanced certification standard exceeding COSC, testing antimagnetic properties and chronometric accuracy.
PP's stringent quality standard certifying movement finishing, reliability, and timekeeping performance thresholds.
Classification system for pavé-set watches based on expected stone retention lifespan.
Manufacturer's declared acceptable rate range and accuracy tolerance.
French name for Geneva Seal, Swiss quality and craftsmanship hallmark certification
Dealer/auction term rating completeness and documentation of watch ownership history from manufacture.
Unique identifier assigned to gemstones exceeding specified weight thresholds.
Standardized procedures by COSC for evaluating chronometer precision and reliability
Maximum allowed variation in seconds per day certified by COSC standards
Early British military watch specification predating modern MIL-W standards, 1940s-1950s.
ISO standard measurement of watch's ability to resist water penetration at depth