Alarm

A pocket watch, wristwatch or clock that automatically sounds at a preset time. The alarm function regained in popularity with the launch, by Eterna in 1908, of a wristwatch with alarm.

Barrel arbor

Supports the barrel and its spring. It comprises a cylinder, known as the core, and a hook to which the inner end of the mainspring is attached. The upper pivot is cut into a square for the...

Combo

A watch with a dual analogue and numerical display.

Display

A system controlled by the watch movement to indicate the time.An alphanumerical (or numerical) display uses letters (or numerals) to show the time.An analogue display gives...

Enamel

A vitreous substance whose main component is silica mixed with oxides (transition metals) that create a vast palette of colours. Enamel is used to decorate metal surfaces, in particular gold,...

Fusee

A more or less conical part with spiral grooves for gut, and after circa 1640 chain, which connects to the barrel. It regulates the power transferred to the gears. Almost all sixteenth,...

Gear train

A system for transmitting power and motion through toothed wheels. In a watch, the train comprises a wheel whose teeth mesh with a pinion's leaves.

Hematite

A natural iron oxide that is a metallic dark to silver-grey with a high sheen. Hematite can be used to make watch dials. It has a specific gravity of 4.95 to 5.16 and a hardness of 6.5 on the...

Independent seconds

A large hand in the centre of the dial, driven by a separate train to the hours and minutes, and making one jump forward every second.

Jewels

The international term for the jewels (rubies) in a watch movement that are used as bearings for pivots to reduce friction. The movement of a quality watch has between 15 and 21 jewels.

Knot

A raised mineral inclusion in a diamond found at the surface.

Luminescent

Having the property to emit light rays. In watchmaking, Tritium is the name given to a radioluminescent substance containing tritium. It was used to coat numerals, markers and hands so they could...

Mainspring winder

The tool used to wind the mainspring before inserting it in the barrel.

Niello

An enamel-like alloy of lead, copper, silver, sulphur and sal ammoniac (ammonium chloride). Niello paste is applied over incised gold or silver then fired in the enamellist's furnace. Excess...

Organic

Describes a substance produced by a living organism. Pearl, coral and shell are examples of organic substances used in jewellery.

Quartz oscillator

The regulating organ in a quartz clock or watch.

Rotor

A semi-circular disc that freely rotates with each movement of the arm to automatically wind the mainspring. Its own weight returns it to a vertical position.A specific system multiplies...

Simple calendar (watch)

Simple calendar: shows the date, i.e. the number, in order, of each day in the month. Certain simple calendars also display the names of the months. A simple calendar...

Trueing calipers

A tool used to calibrate certain parts.

Universal hour

One twenty-fourth of the universal day which begins at midnight at the Prime Meridian at Greenwich. Following the 1884 International Meridian Conference in Washington, the Earth was divided...

Vagues de Genève

Synonym of Côtes de Genève. A decoration of undulating lines, like waves, frequently used to embellish superior quality movements.

Water clock

Water clock: clepsydra with a system of gears.

Year

A four-digit indication of the current year that changes automatically at midnight on December 31st.

Zinc

A metal applied by electrodeposition (electroplating) to protect iron and steel.