AUTOMATIC WATCH a self-winding watch.
BALANCE WHEEL this device -oscillates or swings at a steady rhythm. The rhythm is maintained by a spiral spring at the center of the balance wheel. The source of the energy that drives the balance wheel is another spring, known as the mainspring. The balance wheel feeds its energy to the escapement. If the escapement is the heart of a watch, the balance wheel and its spring are the lungs.
BRIDGE a small plate fastened to the larger base plate of a watch at two points. Moving parts such as -pinions and gear wheels are -attached to bridges.
CALENDAR watches have four types of calendar. Simple calendars only display the date, don't take account of the varying lengths of months and must be reset by hand at the end of each month. An annual calendar takes account of month length, except when February turns to March, and often displays the month, date and sometimes the day of the week. Perpetual calendars usually show the date, month and leap-year cycle, and allow for varying month lengths up to 2100, which isn't a leap year. The rare perpetual secular calendar keeps track of which years, even though dvisible by four, are not leap years, as is the case with 2100.
CALIBRE when used in conjunction with a manufacturer's name and a numerical designation, calibre denotes different iterations of a movement. For example: Tag Heuer Calibre 16 Automatic describes the automatic version of Tag Heuer's calibre 16 movement.
CHRONOGRAPH a watch that displays the time of day and is also a stopwatch. Like a stopwatch, chronographs measure elapsed periods of time of specific events such as races or journeys.
CHRONOMETER a watch that has passed a series of accuracy tests including being subjected to extreme temperatures and position changes. In Switzerland, the testing is performed by the Contrôle Officiel Suisse des Chronomètres (C.O.S.C.)
COMPLICATION any function on a watch other than telling the time of day. Calendars, chronographs, equation of time mechanisms, minute repeaters, power reserves, day/night indicators, moon phase displays and additional time zones are examples of complications.
CÔTES DE GENÈVE one of the most frequently used forms of decoration on Swiss watches. Côtes de Genève, Geneva Stripes in English, are a series of wavy stripes applied to the surface of large, flat components such as bridges and plates.
CROWN the button used to wind a watch and set the time.
CRYSTAL the transparent cover on the front and back of a watchcase. Crystals are usually made from synthetic sapphire but also from glass, plastic and quartz.
ESCAPEMENT this is often described as the beating heart of a watch. The escapement's function is to transfer energy to the time-keeping components of the watch and to accomplish that transference in precisely measured and regular intervals. Put a watch to your ear and the source of the tick-tock sound you hear is the escapement.
EQUATION OF TIME the time shown on watches and clocks is mean -solar time based on the division of the day into neat periods of exactly 24 hours. True solar time, the time on sundials, takes account of the -varying lengths of the day -throughout the year. An -equation-of-time display on a watch shows the difference between mean solar time and true solar time, which can be up to 15 minutes at certain times of year.
GENEVA SEAL (POINÇON DE GENÈVE) since 1886 the canton of Geneva has awarded its official seal to watches that meet a set of stringent criteria. Difficult to obtain, the seal is still a rare accolade found only on the most expensive watches.
GMT WATCH useful for pilots and travelers, most GMT watches have two time zones. One is always set to your home zone while the other is set to a zone you are visiting.
GUILLOCHÉ a form of engraved decoration on watch dials and the cases of pocket watches that is characterized by exquisitely fine, repetitive patterns.
JEWELS they reduce friction by surrounding the rotating steel tips of watch gears and separating them from the metal of plates and bridges. Today jewels are usually synthetic rubies.
LUGS horn-like projections from the case of a watch to which the strap is attached.
LUMINESCENCE visibility in low light or underwater is a feature demanded by many wearers of sports and diving watches. The first luminous watches used radium or tritium, which have fallen from favor because they are radioactive. Today, the most common nonradioactive substance glowing on watches is a strontium aluminate-based substance that is nontoxic and sells under brand names like Super-LumiNova.
MAINSPRING a flat spiral spring that is the source of energy for a watch. When you wind a watch you tighten the mainspring. As the spring unwinds, it sends energy to the other components of the watch.
MANUFACTURE in the watch industry a manufacture, pronounced the French way, is any company capable of producing all the parts of a watch in-house.
MINUTE REPEATER a watch that chimes the hours, quarter hours and minutes on demand. The minute repeater mechanism is a system of hammers and gongs, which are activated by pushing a button on the side of the watch. The button is called a slide.
MOVEMENT the complete watch mechanism with all wheels, gears, plates and bridges plus the escapement and balance. The case, crown, dial, hands and crystal aren't considered part of the movement.
PERLAGE a form of decoration characterized by a pattern of small, overlapping circles. Usually found on plates, bridges and sometimes the inside of cases.
PLATES two flat plates, the main plate and the back plate are the largest components of a watch movement. Along with bridges, plates form the basic framework of the movement.
POWER RESERVE DISPLAY this increasingly popular complication measures how long a watch will run before it needs winding.
QUARTZ WATCH this watch gets its energy from a battery. The battery sends an electric current through a circuit board to a tiny quartz crystal and the crystal vibrates at a constant frequency. The vibrations transfer to another circuit board and the gears that control the hands of the watch.
RETROGRADE DISPLAY another complication growing in popularity. Retrograde displays show hours, minutes or seconds on arcs instead of the usual circular dials. The hands on retrograde displays transcribe the arc, for example, from 1 to 12 for the hours. When the 12th hour is finished the hand jumps back to the 1.
SILICON the element silicon (aka silicium) started appearing in watches about five years ago in parts of the escapement and balance wheel. Its use is expected to grow as the technology for producing silicon components becomes less expensive and more widespread.
SONNERIE a sonnerie watch chimes the hours and minutes en passant like a grandfather clock and not only on demand like a minute repeater. A petite sonnerie chimes on the hour. A grand sonnerie chimes the hour and the quarter hours. These watches are equipped with a device that silences the chimes when desired.
TOURBILLON a rotating platform on which the escapement and balance wheel are mounted. Abraham-Louis Breguet, who patented the tourbillon in 1801, noted that pocket watches gained or lost time depending on their position. The continual turning of the escapement and balance wheel nullifies the effects of these positional errors. Fiendishly difficult to construct but beautiful to observe, tourbillons are highly prized in today's wristwatches. The tourbillon's spinning action led Breguet to christen his creation with the French word for whirlwind.
VIBRATION FREQUENCY the balance wheel of a watch oscillates at a set rate that is measured in hertz (Hz) or vibrations per hour (vph). The most common rates for today's wristwatches are 4 Hz, or 28,800 vph, and 3 Hz, or 21,600 vph.
WATER RESISTANCE water resistance in watches is measured in atmospheres. One atmosphere is equal to 10 meters of water pressure. Most watches are water resistant up to 30 meters. But, if you're planning on swimming or snorkelling, you'll need a watch resistant up to 100 meters. For scuba diving watches resistant up to 200 meters are advisable.
WORLD TIMER a watch that simultaneously shows the time of all 24 of the earth's time zones