Dial: Indicating "face" or plate of metal or other material, bearing various markings to show, in ordinary watches and clocks, the hours, minutes and seconds. Dials vary verymuch in shape, decoration, material, etc. The indications are given by means of numerals, divisions or symbols of various types.
Crown: Knurled knob located on the outside of a watch case and used for winding the mainspring. It is also used for setting the hands to the right time and for correcting thecalendar indications.
Hands: The moving dials on a watch face that points to the hours, minutes and seconds.
Clasp: Connects the open ends of a watch bracelet to secure it to the wrist.
Arabic Numerals: The familiar style of numerals (1, 2, 3, 4, etc.) used on watch faces.
Case: The protective covering enclosing a watch movement, usually made from metal, stainless steel or gold. The watch case includes the bezel, back and movement crystal.
Bezel: The front of a watch case including the rim. Some watches have a bezel that can be rotated to mark elapsed time.
Fly-back Hand: In a chronograph with analogue display, an additional centre second hand which can remain superposed on the other one as it moves, can be stopped independently and then made to "fly back" so as to catch up with the other hand, can be stopped and reset to zero together with the other hand. In chronographs with numerical display, a "function" having the same effect.
Chronograph: A built-in timer or stop watch function.Chronometer: A term signifying watches that conform to a standard set by the Swiss Official Chronometer Control. The board tests watches under various conditions and temperatures to ensure their accuracy.
Crystal: The covering of a watch dial.
Calibre: Originally used to mean the size of a watch movement, this term now denotes a type of movement (men's calibre, automatic calibre, etc). When a calibre number is accompanied by the manufacturer's mark, it serves as an indication of origin.
Deployment Buckle: A clasp that can be opened to increase the size of a closed bracelet.
Jewel: Small sapphires and rubies that act as bearings for the gears in a watch.
Rotor: Half-disc of heavy metal, which is made to rotate inside the case of an automatic watch by the energy produced by the movements of the wearer's arm. Its weight tends always to bring it back to the vertical position. Demultiplied by a specially designed device, its rotations continually wind the mainspring of the watch.
Quartz Movement: A watch movement powered by a quartz crystal.
Mechanical Movement: A traditional watch movement powered by a spring and regulated by a pendulum.
Automatic Self-Winding: Watches that have an internal rotating weight that winds the watch as you move your wrist. Also called kinetic movement.
Rotating Bezel: A bezel around the watch face that can be turned to perform different functions.
Water Resistance: The ability of a watch to withstand water. Measured in feet or meters.
