A plate, with a metal base and visible through a crystal, that carries certain indication, such as the hours, minutes and sometimes seconds.

An additional mechanism in a mechanical watch, e.g. a date or chronographe.

A button, often fluted, on the outside of the watch case used to wind the mainspring in mechanical watches. It is also used to set the time, when pulled out, and for setting a watch calendar. A screw-down crown is used to make the watch more water resistant and to help keep out dust.

A date complication is when the date is displayed on the watch, and it is the simplest complication that exists on a watch. Digital date shows the date displayed numerically through a window (also known as an aperture) on the dial. The date function must be manually adjusted at the end of 30-day months as well as at the end of February to ensure the proper date is displayed.

One of the most important parts of any watch, the escapement provides impulses that maintain the oscillation of the balance wheel ensuring the rate that the escapement will allow the hands to revolve.

Oscillations per unit of time, measured in hertz (Hz). The oldest common standard for wristwatches was 18.000 A:h (2.5 Hz). To increase precision, watch manufacturer later raised the frequency to 21.600 A/h (3 Hz), 28.800 A/h (4 Hz) and more.

The pointing device anchored at the center of and circling around the dial indicating hours, minutes, seconds and any other special features of the watch.

Synthetic sapphires or rubies that act as bearings for gears of a mechanical watch. A quality hand wound or automatic mechanical watch contains at least 17 jewels.

Curved attachment of the watch case to attach the bracelet, strap or band.

Luminous (lume) markers and hands are made by applying glow in the dark coating to the indicator. This allows them to illuminate automatically in a darkened environment.

Mechanical watches are the most traditional type of watch. They usually consist of about 120-180 individual parts. This is a watch that runs without any electrical source and can consist of manual wind watches or automatic watches. When wound, it slowly unwinds the spring in an even motion. An automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist.

Heat hardened glass about ten times harder than plastic. Hardness level 5.

The engine of the watch, The fully functioning assembly of all the main timekeeping organs of a watch. Three main movements include mechanical, automatic and quartz.

Quartz watches are battery powered. They can either have hands, like the more traditional mechanical watch, or have a digital display. These watches are much more accurate than even the most expensive manual wind watches.

The part of an automatic watch that rotates as it is worn to wind the main spring.

The back of the case has a thread so that it can be screwed into the case.

The shock absorber is a bearing that captures the shocks taken by the balance staff and protects its pivots from being damaged.

A prohibited term used when describing the water resistance of a watch. No watch can be fully 100 percent waterproof.

The ability of a watch to resist splashes of water. This will indicate the depth that a watch can be worn underwater.
Water resistant:
Withstands splashes of water or rain but should not be worn while swimming or diving

Water tested to 50 meters (165 feet):
Suitable for showering or swimming in shallow water

Water resistant to 100 meters (330 feet):
Suitable for swimming or snorkeling

Water resistant to 200 meters (660 feet):
Suitable for scuba diving