A-Z

Watch Terms A-C

A

• Acrylic

A plastic used to make crystals. It's very soft, but is easy to repair and does not shatter when it breaks. Watches designed for use in space have acrylic crystals.

• Analog

A display of time or other data using dials and hands, as opposed to a digital readout. After a hiatus in the 1980s, the format has become increasingly popular.

• Analog-digital display

A watch display that combines analogue and digital elements, usually found on Quartz watches, though there are some mechanical versions

• Anti-magnetic

A type of mechanical watch movement that is designed to be highly resistant to magnetic fields that could adversely affect or stop it.

• Automatic winder

A box or cabinet with motorized rotating slots to hold watches with automatic movements. The rotation keeps the watch wound by spinning the movement's rotor, and accurate by counteracting the effects of gravity. Some winders are incorporated into special safes to hold collector automatic watches that cost six figures.

• Automatic winding

Also called self-winding or simply automatic. A mechanical watch movement that is wound by the motions of the wearer by either spinning a rotor or oscillating a weight. Failure to wear the watch regularly will cause it to stop once its power reserve is exhausted.

• Balance

The oscillator on a mechanical watch that regulates the movement so it runs in a series of beats or vibrations.

• Balance spring

See Hairspring.

• Balance wheel

An oscillating wheel that regulates the movement by dividing time into regular beats

• Balance cock

A bridge with a lug anchored to a stud. It holds the top pivot of the watch's balance staff.

• Bezel

A ring around the watch face made of stainless steel, ceramic, precious metal or base metal. It can be either decorative or movable. If the latter, it may be inside or outside the crystal and rotate to act as a timer, tachymeter, slide rule, or other function.

• Bi-color

See Two-tone

• Bi-directional rotating bezel

A bezel that can rotate either clockwise or anticlockwise to perform a function.

• Bracelet

A watch band made of movable links. These can be adjusted to fit the wearer and may have special clasps that allow them to expand to fit over a wetsuit or jacket.

• Bridge

A plate or bar set on a movement's main plate to act as a frame to hold a watch's inner workings. They can also be shaped or decorated in skeleton watches for aesthetic purposes.

• Calendar

A complication that shows the date and may also show the day of the week, the month, or even the year. Some calendar watches need to be adjusted manually whenever the month is less than 31 days long. Others, called perpetual calendars, are self-adjusting over several decades or centuries.

• Caliber

See Movement.

• Cambered

An arched or curved bezel or dial.

• Case

The housing used to protect the movement. Usually made of base or precious metal, it can also be made of plastic, carbon composite, ceramic, rubber, or other materials.

• Case back

The back or reverse of a watch designed to protect the movement. These are generally made of stainless steel, though they may include a crystal to show off the workings inside. Case backs may be simply snapped in place or screwed in with rubber gaskets to protect against water and dust. These often include information about the watch, like hallmarks, major specifications, or a serial number.

• Chapter ring

A ring of symbols or marks on a watch dial to indicate minutes or seconds.

• Chapters

Large marks on a chapter ring to denote hours. Quarter hours often have their own chapters.

• Chronograph

A complication that allows a watch to act as a stopwatch with a precision of down to a tenth or a hundredth of a second. Some versions allow lap timing as well for individual contestants in a race or events in a process.

• Chronometer

A precision timepiece capable of keeping time with a precision and accuracy suitable for navigation. Swiss-made watches are certified as chronometers by meeting the standards set by the Swiss Official Chronometer Control (COSC), which includes several days of rigorous testing under various pressures and temperatures.

• Clasp

Fastening mechanism for straps and bracelets. Leather, rubber, and cloth bands tend to use buckles, though bracelets and expensive leather straps use deployment straps for a tighter fit with less wear.

• Complication

Any function on a watch beyond displaying hours, minutes, and seconds. These can include even unseen things like an automatic winding function.

• Cosmograph

A chronometer developed and named by Rolex that has a tachymeter mounted on the bezel instead of the dial.

• Countdown timer

A complication that counts down in reverse from a preset time, like for timing an egg or a parking meter. This can include an alarm to alert the wearer when the time has elapsed, though that is usually found on quartz watches.

• Counterfeit watch

An illegal copy of a watch that is passed off by the maker as the real thing.

• Crown

A button on the side of the case that pulls or screws out, allowing the wearer to adjust the time and date or synchronize the seconds. In non-automatic watches, it is also used to wind the mainspring. Screw-in or screw-down crowns, or similar mechanisms, seal the watch to keep out water at extreme depths.

• Crystal

A transparent cover over the dial or in the case back, or it may make up the entire case. It can be made of ordinary glass, mineral glass, acrylic plastic, synthetic sapphire, or ruby. Sapphire is preferred for high-end watches because it's almost as hard as diamond, though many use plastic because it's easy to repair and cracks instead of shattering into small, potentially dangerous fragments.

• Cyclops

A small blister on a crystal that acts a magnifying lens to make the date more legible.