Watch Glossary

Swiss-French horologist who revolutionized watchmaking with innovations like the tourbillon and Breguet spiral

GMT-Master II with black and blue bezel insert, resembling Batman's color palette.

Auction house observation of competitive escalation causing buyers to exceed pre-sale estimates.

Balance wheel made of two different metals to automatically compensate for temperature changes

Auction term for providing minimal provenance documentation on vintage pieces to reduce liability.

Hairspring with specially shaped terminal curve invented by Abraham-Louis Breguet for improved chronometry

Verification process confirming genuine Crown military issuance by examining hallmark placement and stamps.

Case back stamped with broad arrow symbol denoting British or Commonwealth military issue.

Standardized position on case back or lug area where broad arrow stamp is applied.

British military property mark denoting Crown ownership; stamped on case back or dial of service watches.

Authentication marker establishing military issuance history through official Crown ownership symbols.

Measurement of how accurately a chronometer maintains timekeeping over extended periods

Standard of accuracy required for movements to be officially certified as chronometer-quality

GMT-Master II with red and black bezel insert, resembling Coca-Cola branding.

Specialized dial for commercial diving watch, often with unique printing or design.

Balance wheel designed to maintain accurate rate despite temperature fluctuations

Historical device used to adjust effective hairspring length for rate regulation

Historical watch model series emphasizing robust construction

Robust nautical timepiece used on ship decks, predecessor to modern dive watches.

Escapement design where the balance wheel operates independently during most of its oscillation

Collector authentication term for reference collection maintained by reputable vintage dealers.

Auction documentation extracted from original manufacture archives confirming watch production details.

German military pilot watch with dial designed for excellent readability in aircraft cockpits.

Balance wheel without a regulator index, relying solely on the hairspring for rate adjustment

Conical spool that equalizes mainspring force through variable mechanical advantage

Hallmark certifying excellence in watchmaking, awarded by Geneva Canton

Watch combining multiple complex functions like perpetual calendar and minute repeater

Harrison's innovative escapement mechanism using three pivoted pallets for efficient energy transfer

John Harrison's first marine chronometer, completed in 1735 using a grasshopper escapement

Harrison's pocket watch-style chronometer that won the Longitude Prize with remarkable accuracy

Vintage watches where date changes coincide with hour hand position at midnight.

High watchmaking; artisanal craftsmanship producing exceptional mechanical timepieces

Relating to the science, study, and art of timekeeping and watch design

Master craftsperson specializing in the design, construction, and repair of clocks and watches

Green Submariner Date reference 116610LV, named for its vibrant hulking green color.

Property where oscillation period remains constant regardless of amplitude or driving force variation

Synthetic ruby or sapphire holes that reduce friction in watch movements through low-friction surfaces

English clockmaker who solved the longitude problem with his marine chronometers H1-H5

Green Submariner with green bezel, nicknamed after Kermit the Frog character.

British competition offering substantial reward for solving maritime longitude determination problem

Challenge of determining a ship's east-west position at sea, solved through precise timekeeping

Container holding the mainspring that stores and releases energy to power the watch

French for house; prestigious watchmaking company with heritage and identity

Highly accurate navigation instrument used aboard ships to determine longitude at sea.

Average solar day length used as standard for watch regulation before atomic time

Submariner depth rating printed as meters before feet, rare vintage dial variant.

Rate variation at intermediate temperatures despite compensation mechanisms

Military Submariner issued to armed forces, featuring lollipop dial and dial printing variations.

Watch officially issued by British Ministry of Defence to military personnel for field operations.

Official record documenting authorized changes to military-issue watches during service life maintenance.

Marking applied to watches serviced through official British military maintenance channels.

Physical property of balance wheel oscillation that enables continuous operation without external intervention

Omega Speedmaster Professional, official NASA moon landing chronograph from Apollo missions.

Reference number assigned to military watch procurement contracts in NATO inventory system.

Engraved NATO identification number on military watch case or bracelet connector bar.

International cataloging system assigning unique identification codes to military watches.

Additional outer coil on hairspring that improves isochronism and temperature stability

Components of escapement that engage and release the escapement wheel in precise intervals

Historical hallmark symbol punched on PP movements and cases, representing brand heritage since 1932.

Iconic Rolex Daytona worn by actor Paul Newman, named after the exotic dial variant he preferred.