Watch Glossary
1104 horological terms explained · 11/19
Challenge of determining a ship's east-west position at sea, solved through precise timekeeping
Number of seconds per day a watch runs behind correct time.
Adding appropriate lubricants to watch components for smooth mechanical operation
Protruding attachment points on the watch case where bracelets or straps connect.
Space between the lugs where the strap or bracelet attaches.
Measurement between watch case attachment points determining wrist fit compatibility
Measurement between the inner edges of the lugs, determining strap and bracelet fit on the wrist.
Projections on the case that hold the strap or bracelet.
Abbreviation for luminous material applied to hands and markers.
Radioactive or photoluminescent coating on hands and indices for night visibility
Process of applying luminous material to watch dials, hands, and hour markers
Initial intensity of luminescence immediately after light exposure before degradation occurs
Luminous fill color; typically green, blue, or white for underwater visibility.
Quality of luminous material to adhere properly to dial surface without peeling or degrading
Visual difference between luminous and non-luminous dial areas visible in darkness
Percentage and area of watch dial, hands, and indices coated with luminous material
Gradual loss of luminescence brightness and duration in watch hands and dials over extended time
Dial coated with luminous material for low-light visibility
Process of filling dial cutouts with luminous material for enhanced visibility and aesthetics
Duration and persistence of a watch's luminous glow, measured in hours of visibility in darkness
Consistency between luminous brightness levels on dial, hands, and markers in darkness
Aged appearance of vintage luminous material showing discoloration, yellowing, or browning over time
Resistance of luminous coatings to fading, degradation, and environmental exposure over time
Area of luminescent material applied to hands for extended visibility in darkness
Applied luminous hour markers on dial, typically rectangular shapes on vintage sports watches
Photograph of a watch taken in darkness showing the glow of luminous materials on dial and hands
Amount of luminous material applied to watch components affecting brightness and durability
Consistent application of luminous coating across dial ensuring even brightness throughout
Advanced luminous material providing superior glow intensity and longer phosphorescence duration.
Hour markers filled with luminescent material enabling nighttime visibility
Seiko's luminous coating providing bright glow and long-lasting luminescence on watch dials
Measure of how brightly and for how long a watch's luminous material glows in darkness
Glow-in-the-dark hour markers and hands enabling underwater visibility in darkness.
Phosphorescent coating on hands and indices enabling visibility in darkness.
Radium-free glowing paint applied to watch hands and markers for low-light readability enhancement.
Indicator showing lunar month cycles, typically 29.5 days, advancing with gearing system.
Omega's proprietary gold alloy designed to resist scratches and maintain its luster indefinitely.
Multi-axis magnetometer detecting geomagnetic orientation for compass functionality
Unwanted magnetic fields that can disrupt watch timekeeping accuracy.
Optical enlargement of dial elements, typically date windows, using sapphire or acrylic lenses
Coiled metal ribbon that stores energy to power the entire watch movement.
Container holding the mainspring that stores and releases energy to power the watch
Replacement of power source spring that drives watch movement
French for house; prestigious watchmaking company with heritage and identity
Mechanical movement requiring manual winding via the crown to store energy in mainspring.
Integrated watchmaking company producing movements in-house from components to assembly
Watch movement entirely designed and produced in-house by a single manufacture
Highly accurate navigation instrument used aboard ships to determine longitude at sea.
Luminous coating on hour markers and indices for improved nighttime readability
METAS certification for watches exceeding traditional chronometer standards
Non-reflective black surface coating offering stealth appearance
Diamond-like carbon coating in matte black finish, combining hardness with non-reflective aesthetics.
Non-reflective dial finish, typical of vintage sports watches and highly desirable to collectors
Non-reflective surface with minimal shine, absorbs light evenly
Rolex's larger hour markers and hands introduced for improved readability
Average of gaining and losing rates across multiple positions.
Average solar day length used as standard for watch regulation before atomic time
Seiko's hybrid movement combining quartz accuracy with mechanical automatic winding.
Exactness of manufacturing tolerances affecting timekeeping performance.
Design architecture integrating traditional watch complications with electronic displays