The essential watch terms explained simply, from the most common to the most technical. Each definition fits in one or two sentences.
The movement
- Calibre
- The model of a watch's movement, identified by a reference (for example ETA 2824 or Rolex 3235).
- Automatic movement
- A mechanical movement that winds itself through a rotor driven by the motion of the wrist.
- Manual winding
- A mechanical movement without a rotor, wound by turning the crown.
- Quartz
- A battery-powered movement regulated by a quartz crystal vibrating at a constant frequency.
- Rotor
- The half-moon-shaped oscillating weight that pivots with your movements and winds the mainspring of an automatic watch.
- Barrel
- A small drum containing the mainspring, the watch's energy store.
- Slipping bridle
- A device in the barrel that slips once the mainspring is fully wound, making overwinding impossible.
- Power reserve
- How long a watch keeps running without being worn or wound, often 38 to 80 hours.
- Balance spring
- The regulating organ that oscillates at a steady rhythm and determines accuracy.
- Escapement
- The mechanism that releases the mainspring's energy to the balance in small impulses.
- Frequency
- The number of oscillations of the balance, expressed in vibrations per hour (for example 28,800 vph) or in hertz.
- Jewels
- Synthetic rubies used as bearings to reduce friction.
Complications
- Complication
- Any function beyond the hours, minutes and seconds.
- Date (simple calendar)
- Displays the day of the month; it must be corrected by hand at the end of short months.
- Annual calendar
- A date that handles 30- and 31-day months, needing correction once a year at the end of February.
- Perpetual calendar
- A date that also handles February and leap years, with no correction needed for decades.
- Moon phase
- A disc that reproduces the lunar cycle of roughly 29.5 days.
- GMT
- An additional hand that shows a second time zone on a 24-hour scale.
- Chronograph
- A timing function, started and stopped with pushers.
- Tourbillon
- A rotating cage holding the escapement, designed to offset the effect of gravity.
The case and its details
- Crown
- The button on the side used to wind the watch, set the time and often the date.
- Bezel
- The ring around the crystal, sometimes rotating.
- Sapphire caseback
- A transparent back that shows the movement.
- Sapphire crystal
- A synthetic crystal that is highly scratch-resistant.
- Lugs
- The parts of the case where the strap is attached.
- Deployant clasp
- A folding clasp that saves a leather strap from being bent each time you put the watch on.
Storage and care
- Watch winder
- An accessory that rotates an automatic watch to keep it wound when it is not being worn. See our watch winders.
- TPD (turns per day)
- The number of rotations a watch winder makes each day, usually 650 to 800. See the table by brand.
- Rotation direction
- Clockwise, anticlockwise or bidirectional, depending on the calibre.
- Service
- A complete dismantling, cleaning and lubrication of the movement, every 5 to 10 years depending on the brand.
- Demagnetisation
- A quick procedure that removes magnetism from a movement. See magnetism.
- Water resistance
- Resistance to water, expressed in metres or bar, which should be checked regularly.
FAQ
What is the difference between a calibre and a movement?
The movement is the engine of the watch; the calibre is the name of that engine's model.
What does 28,800 vph mean?
The balance makes 28,800 vibrations per hour, or 4 hertz: a common frequency in modern watches.