What's a chronometer? What's a Moon Phase? Here's a glossary of watch terms you need to know.
A mechanism that uses the wearer’s arm movements to cause a rotor to rotate, which in turn − through various gears − winds the mainspring.
The first electronic watch, launched by Bulova in 1960 and controlled by a tuning fork.
An oscillating device that regularises the movement of a watch’s going train of or clock. In modern watchmaking, balances are almost always circular and monometallic.
The central body of a watch case to which the movement, covers, bezel and pendant are fixed.
The ring on a watch case that secures the crystal. A rotating bezel records additional information. The bezel on a diving watch is unidirectional as an added safety element for divers.
Polished precious stone that is usually domed. It also refers to the embossed ornament on a dial.
Exactly as the term says − a case on the back of the watch, covering the movement.
Science of accurate time measurement.
Etymologically, any instrument for measuring time. In actual usage, the word has been given another sense -- a precision instrument. A very good watch is sometimes referred to as a regular chronometer.
The Swiss Federation of Watch Manufacturers’ Associations (F.H.) defines the chronometer as a watch that has obtained an official rating certificate.
In Switzerland, the main issuing body is currently C.O.S.C..
A chronograph can only use the name “chronometer” if it has been certified as such. a chronograph watch has hour, minute and second hands along with a mechanism controlling the chronograph hand.
The button used for winding of the movement and setting of the time.
The protective transparent cover over the dial, made from glass, plastic, synthetic sapphire or rock crystal.
The watch face with markings of hours, minutes and seconds. Dial designs vary in shape, decoration and material.
The hour markers are painted with a luminous salt. It is alternatively known as radium dials. They were already in use during World War I.
Now, a dial can be illuminated using miniature bulbs under the bezel.
Found on precision timekeepers, there is a central minute hand and subsidiary dials for the hours and seconds.
This helps a watch run accurately for longer as the case prevents dust from getting into the watch movement and affecting its timekeeping ability.
A hand, on a chronograph, that makes one rotation every second. It is used to time fractions of a second.
Ornamental shimmering patterns, the brightness of which is enhanced by transparent enamelling. This process was done by hand on dials and watch cases as early as the start of 17th century.
A device for adjusting a watch’s rate by increasing or reducing the effective length of the balance spring. The index is a steel lever with two arms − the shorter of which carries the pins embracing the spring, the other one acting as a pointer that is also called the tail or arrow, the end of which can move over a graduated scale.
The markers or divisions on the dial to indicate the hours and minutes.
An aperture or subsidiary dial showing the progression of the moon.
In a non-magnetic watch, the balance, balance-spring and escapement are made of nonmagnetic metals or alloys as they are the most vulnerable to a magnetic field. Alternatively, the watch’s movement is protected by a magnetic screen.
A detailed rating certificate that is issued by an observatory or by an official watch rating bureau. Only a watch with this rating certificate can be called a chronometer.
A very hard, brittle, stainless, non-magnetic white metal. It has been used for making balance springs and more recently as a case material.
The going duration of a watch, that is the remaining energy in the spring. It is indicated by a dial or a sector on the dial.
Small cylindrical tools of hardened steel used by watchmakers for repair jobs such as riveting and pin-extracting. This type of punch is held in the hand and struck with a hammer. Punches are also used for marking parts with figures, letters or symbols.
Button that is pressed to work a mechanism such as in a chronograph.
Silicon oxide or rock crystal used in making a watch crystal. In the 16th and 17th centuries, watch cases were made of it. It is sometimes yellow (citrine) or violet (amethyst) but pure quartz is colourless.
Watch that strikes the hours by means of a mechanism operated by a push-piece or bolt. Types of repeaters include Quarter-repeater (that sounds for each of the quarters); minuterepeater (striking the hours, quarters and minutes) and grande sonnerie (grand strike) which strikes the hours and quarters automatically and repeatedly when the corresponding push-piece is pressed down.
A hand which passes through the arc of a graduated sector (portion of a circle) and upon reaching the end, returns instantaneously to the first indication.
Whole turn of a rotating body. The centre wheel completes one revolution in an hour.
The most suitable natural stone for the bearings of the escapement of a watch.
A watch which movement is protected against shocks.
Parts of the movement on this timepiece made from transparent material, enabling the main parts of the movement to be seen.
Metal is used in case and movement manufacture in modern watchmaking.
Sources: Foundation High Horology and Antiquorum-Lexico.
