The military and aviation name for Greenwich Mean Time (GMT) or Coordinated Universal Time (UTC) working on a 24 hour clock where the Greenwich Meridian is in the zero (Z) hours time zone. Since in the NATO phonetic alphabet "Z" is "Zulu", pilots and military operations work to "Zulu Time" - a constant wherever they ar [..]

Another name for the Crown. The knob used for setting the time and winding the spring.

The larger gears in a watch which are often spoked. Solid smaller gears are called Pinions.

A self-powered light source based on an isotope of Hydrogen used to make the markings on a watch dial legible in the dark. It is not a radiation hazard since it is a low energy beta emitter, but it has been superseded in most watches now by more natural pigments like Luminova. With a half life of just over 12 years, Tritium will slowly fade and be [..]

A clever addition to the Escapement to help maintain accuracy, a Tourbillon counters the effects of changes in the position/angle of the watch. It allows the escapement to rotate independently within the watch so that it maintains a consistent position in relation to gravity. First developed in the 1790s, Tourbillons are not really necessary in mod [..]

The shaft that sticks out of your pocket watch with the Crown on the top … thus a Stem Wound watch.

Another name for a Register

A watch with the Movement on display. The Dial consists of only the Chapter Ring with the hours and minutes around the outside, the rest is clear allowing you to see the Movement, Balance Wheel, Jewels etc … Some Skeleton Watches have Crystal backs to allow the Movement to be viewed from both sides.

This is a watch where the Stem emerges from the watch at 3:00 rather than at 12:00. This is pretty common with Hunter Cases because it makes the time easier to read when you open a Hunter - as you hold it in your right hand and press the Stem with your thumb to open the lid, 12:00 ends up naturally in the correct uppermost position.

An additional Register dial that shows the time in a different time zone.