Watchmaking

Watchmaking glossary

Tongue : Long part which fits into one of the holes in a strap and generally forms part of the buckle.

Balance : Device which, by oscillating, regularizes the movement of the train of a watch or clock.

Case : Casing that protects the watch-movement from damp, dust and shocks. The case can have different shapes and materials. It is meant to protect the mechanism.

Deployant Clasp : System of small, curved metal plates and hinges, which allow the layers to fold over each other, to close the bracelet.

Dial : Indicating “face” or plate, bearing various markings to show, in ordinary watches, the hours, minutes and seconds.

Caliber : Term that indicate the shape of the movement and its bars, the origin of the watch, the designer's name.

Chronograph : Complication of awatch allowing measurement and display of time intervals.

Chronometer : A precision instrument. A very good watch is sometimes referred to as a regular chronometer. In Switzerland the term Chronometer is discerned by the COSC (Contrôle Officiel Suisse des Chronomètres).

Complication : Any additional function a watch might deliver, other than the display of hours, minutes and seconds. The most common ones are: date, moon phase and chronograph.

Horn : Parts usually made flush with the case-band and they allow the strap to be fastened onto the case.

Crown : Small knob which sits outside the case and allows the user to wind the mainspring and set the time.

Hour-makers : Variously shaped symbols substituted for numerals on some dials.

Luminescence : Act or power of emitting light-ray, on index or hands it’s allowed the reading of time in the dark.

Bezel : Ring snapped on to the middle of a watch-case to hold the glass. Bezels can be fixed or rotating.

Manufacture : In the Swiss watch industry, the term manufacture is used of a factory in which watches are manufactured almost completely.

Movement : Name of the mecanism of watches maintaining the timekeeping. It can be mechanical or electrical.

Moonphase : Complication showing the phases of the moon, variable apparent shapes of the moon during its revolution around the earth.

Power reserve : Length of time during which a mechanical wristwatch can operate without being wound.

Skeleton watch : Watch in which the case and various parts of the movement are of transparent material, enabling the main parts of the watch to be seen.

Tachometer : Instrument for measuring speed.

Tourbillon : Complication which contains components allowing the oscillating balance wheel to be driven in a tiny mobile cage, at the rate of one revolution per minute. This complication, considered to be one of the most prestigious, allows the movement to be perfectly adjusted.

Trotteuse : French term for a direct drive seconds-hand, especially a center seconds-hand.

Glass : Component of the case that allows the dial to be seen while closing the case. It can be made of plexiglass, mineral glass or artificial sapphire.