W - X

Watch - A watch comprises four essential parts: the movement, the case, the dial and the hands.

Watch Winder - a powered device that keeps a watch wound and running when not on a wearer's wrist.

Waterproof - in most markets watches can not be described as waterproof.  Watches must be marked as "water-resistant" followed by a depth rating.

Water resistant - ability to withstand water pressure. Made to prevent water from entering a watch.  The watch case joints are made to prevent moisture from entering. Water resistance is measured in meters and refers to the depth that the watch will keep out water:
                                  50 meters    surface swimming
                                100 meters    snorkelling
                                200 meters    scuba diving (to 40 meters)
                             1,000 meters    deep sea diving. 

Wheel -

(pinion) Circular part revolving round an axis to transmit power or motion. The principal wheels are:
            - The centre wheel
            - The column wheel 
            - The fourth wheel
                                           - The hour wheel
                                           - The minute wheel                                
                                           - The third wheel
                                           - The transmission wheel    

White gold - created from yellow gold by incorporating either nickel or palladium to the alloy.
                    75% Gold, 16% Palladium, 9% Silver

Winding - tightening the mainspring of a watch.  This is done by hand (turning the crown) or automatically (by the motion of the rotor).

Winding Stem - see Stem