A mechanical watch that is powered by the motion of the wearer. It needs no winding or batteries.
Sometimes known as a hairspring, this is attached to the balance wheel to regulate its rate of oscillation.
Regulates the time and moves the watch’s hands by oscillating at a constant rate to power the watch’s gears.
A cylinder with geared teeth that houses the mainspring.
The ring that surrounds the face of the watch. Usually made of metal or ceramic, they can be purely decorative or functional. Some have scales that can be used as tachymeters and bezels on dive watches can be rotated to indicate time elapsed under water.
Part of a mechanical watch that is mounted to the mainplate to make a frame to house the inner workings.
Another word for “movement”.
The under side of the watch face. Some are made of crystal to display the movements inside.
A watch that features a stopwatch function.
A watch certified by the Contrôle Officiel Suisse des Chronomètres (COSC). Mechanical watches must be accurate to within +4 and -6 seconds per day and quartz watches by ±0.07 per day.
Any function of a watch other than simple time indication.
The knob on the side of the watch case that is used to wind the watch and/or set the time and date.
The “glass” that protects the face of the watch. It is usually made from acrylic, glass or synthetic sapphire.
A strap closure that folds in itself to be held in place with a clasp. They can extend the life of leather straps as they avoid the damage sometimes caused by buckles.
The face of the watch featuring numeral markings and manufacturer branding.
A watch specifically designed for divers. Most are water-resistant to 200 metres, have luminous hands and moving bezels to signal the amount of time the diver has spent underwater.
The part of the watch that moves the second hand and is responsible for its ticking.
A stopwatch that can record multiple times.
The speed at which a watch ticks, governed by the oscillations of the balance wheel.
The rubber or plastic ring used to seal gaps when closing the case back. Prevents the entry of water or dust.
The system that powers the escapement from the mainspring.
Stands for Greenwich Mean Time but describes any watch that has an extra hour hand so the time in two zones can be indicated at once.
A function that stops the seconds hand when the crown is pulled out allowing synchronisation with other timepieces.
One interested in the science, or art of time. Also a maker of clocks or watches.
The science, or some may say art, of measuring time.
Hour markers applied to the face of the watch.
Synthetic rubies or sapphires used to reduce friction in the movement of a watch.
The pieces of metal at the top and bottom of the case that are used to attach the strap or bracelet.
The glow given to numerals and hands, typically on dive watches. Most watch manufacturers use strontium aluminate which is not radioactive.
The loss of accuracy caused when the balance spring becomes magnetised. This is easily remedied by a watchmaker, but some watches are anti-magnetic, with the movement protected by soft iron cages. Balance springs can also be made of silicon, which cannot become magnetised.
The base of a movement on which all the mechanical parts are mounted.
The spring that is tightened when the watch is wound. The unwinding of the spring powers the watch.
A company that develops its own parts and movements rather than buying them from suppliers.
The mechanism that powers all the functions of the watch. Can be automatic, hand-wound or battery powered (quartz).
The length of time a fully-wound automatic watch will continue to run if it is not worn or moved.
A battery-powered watch.
A watch that chimes to tell the time in response to the push of a button.
A watch with a dial that has gaps to display the movement from the front.
A second, smaller dial on the watch’s face that displays the seconds.
An escapement housed in a rotating cage to counter the effects of gravity on the movement. They usually feature on very high-end watches and are displayed through a hole in the watch’s face.
A rotating box that keeps an automatic watch fully wound when it is not being worn.