WatchesAtlas / Watch knowledge
The Watch Encyclopedia
Understand the details that make a watch.
562 terms
12-hour bezel
A bezel carrying a 12-hour scale that can assist a second time-zone reading.
Cases, dials & bracelets24-hour bezel
A bezel with a 24-hour scale, commonly paired with a corresponding GMT hand.
Complications & displays24-hour display
A time indication that completes or represents a full 24-hour cycle rather than repeating a 12-hour cycle.
Modern watch technologyAccelerometer
A sensor measuring acceleration, used in selected watches for motion-related functions.
Performance & measurementAccuracy
How closely a watch's indicated time corresponds to a reference over a stated interval.
Cases, dials & braceletsAcrylic crystal
A plastic crystal that is relatively light and can often have minor scratches polished out.
Performance & measurementAdjustment in positions
Work intended to reduce differences in a movement's running behaviour across specified orientations.
Collecting, condition & careAftermarket part
A component supplied outside the original manufacturer's official parts channel.
Complications & displaysAlarm
A function producing an alert at a selected time, mechanically or electronically.
Collecting, condition & careAll-original condition
A claim that a watch retains its originally supplied components or configuration; its scope requires evidence.
Cases, dials & braceletsAlpha hands
Hands with a broad tapered body leading towards a narrow point.
Complications & displaysAltimeter
A function estimating altitude, commonly using pressure readings or electronic information.
Modern watch technologyAlways-on display
A display mode maintaining a visible indication while managing brightness, refresh or energy consumption.
Complications & displaysAM/PM indication
An indication identifying which half of a 24-hour day is associated with a time display.
Performance & measurementAmplitude
The angular extent of a balance wheel's swing, measured under stated test conditions.
Modern watch technologyAna-digi
A display combining analogue hands with a digital readout.
Finishing & craftsmanshipAnglage
The creation and finishing of bevelled edges on movement components.
Complications & displaysAnnual calendar
A calendar mechanism accounting for different month lengths but normally needing a correction around February.
Cases, dials & braceletsAnti-reflective coating
A surface treatment reducing reflections from a crystal to improve visibility.
Cases, dials & braceletsAperture
An opening in the dial through which an indication, such as a date, can be read.
Complications & displaysApparent solar time
Time based on the Sun's apparent position, differing through the year from mean solar time.
Cases, dials & braceletsApplied indices
Hour markers attached to the dial as separate parts rather than printed directly on it.
Movements & mechanismsArbor
A shaft supporting a rotating movement component and transferring torque where required.
Collecting, condition & careArchive extract
A manufacturer document reporting information from historical records, which is not necessarily a complete authentication of current condition.
Cases, dials & braceletsAsymmetric case
A case whose form is intentionally not symmetrical across its principal axes.
Performance & measurementATM
A pressure unit often used in water-resistance markings.
Collecting, condition & careAuction estimate
An auction house's indicative expected price range, which is not a guaranteed selling price or valuation.
Collecting, condition & careAuction lot
An item or group of items offered as one unit in an auction.
Collecting, condition & careAuction provenance
The recorded history of a watch's appearance and sale in auction catalogues or results.
Collecting, condition & careAuthentication
Assessment of whether a watch and relevant components correspond to what they are claimed to be.