Reference
Watch glossary
Plain-English meanings of the watch terms used across this site, with links to the guides.
31 of 31 terms
- Automatic (self-winding)
- A mechanical watch wound by a weighted rotor that swings as you move. Automatic watches →
- Balance wheel
- The oscillating wheel and hairspring that regulate a mechanical watch, swinging back and forth at a steady rate.
- Beats per hour (bph / vph)
- How many times the balance ticks per hour. 28,800 bph is 8 beats a second (4 Hz); a higher rate gives a smoother-looking seconds hand.
- Bezel
- The ring around the crystal. It may be fixed or rotate, as on dive and GMT watches. Bezel timer →
- Calibre (caliber)
- The movement's model name or number. One calibre is often used in many watch models, so manuals are frequently listed by calibre. Finding your model number →
- Case back
- The back of the case, often engraved with the reference, calibre and water-resistance rating.
- Chronograph
- A built-in stopwatch, started, stopped and reset with pushers. Chronograph guide →
- Complication
- Any function beyond hours, minutes and seconds, such as a date, chronograph, GMT hand or moonphase. Watch functions →
- Crown
- The knob used to wind and set the watch. Most have several pulled-out positions. Setting a watch →
- Crystal
- The transparent cover over the dial, commonly sapphire (very scratch-resistant), mineral glass or acrylic.
- Dauphine hands
- Tapered, faceted hands that catch the light, common on dress watches. Hands and indices →
- Escapement
- The mechanism that releases the mainspring's energy in small, regular steps, producing the tick.
- GMT hand
- An extra hand that goes round once every 24 hours, used to show a second time zone. GMT explained →
- Hacking
- A feature that stops the seconds hand while you set the time, so you can start it exactly on the second. Setting the time →
- Indices (hour markers)
- The markers at each hour: batons, numerals, dots and more. They may be printed or applied. Hands and indices →
- Jewels
- Synthetic rubies used as low-friction bearings in mechanical movements. The count reflects design, not value.
- Lugs
- The projections on the case that hold the strap or bracelet. Lug width is the gap between them. Strap and lug width finder →
- Lume
- Luminous material on hands and markers that glows in the dark after being charged by light. Lume guide →
- Mainspring
- The coiled spring that stores energy in a mechanical watch.
- Manual-wind
- A mechanical watch wound by turning the crown, usually daily. Movements →
- Moonphase
- A display showing the Moon's phase through a window on the dial. Moonphase guide →
- Movement
- The watch's engine: quartz, automatic, manual-wind or solar. Movements →
- Power reserve
- How long a fully wound mechanical watch (or a charged solar one) runs without more energy. Automatic watches →
- Quartz
- A battery-powered movement regulated by a vibrating quartz crystal; usually very accurate. Movements →
- Quickset
- A crown position (or pusher) that changes the date, or another display, without turning the hands all the way round. Setting the date →
- Reference number
- The manufacturer's code for a specific model, used to find manuals, parts and straps. Finding it →
- Rotor
- The weighted half-disc in an automatic watch that winds the mainspring as you move. Automatic watches →
- Screw-down crown
- A crown that screws onto the case to help keep water out. Unscrew it before setting and screw it back afterwards. Water resistance →
- Solar
- A quartz watch recharged by light through the dial, so the battery rarely needs replacing. Movements →
- Tachymeter
- A scale for working out speed from elapsed time over a known distance, used with a chronograph. Watch functions →
- Water resistance (ATM / bar / m)
- A rating from a lab pressure test. It isn't a safe diving depth, and seals age. Water resistance guide →