From 'Alarm Watch' to 'Zodiac'...

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This page is a glossary of terms associated with horology, watches and watchmaking, please click one of the links above. If you would like us to list any other words that you think may be helpful, please contact me direct chris@christopherward.co.uk  

U - WATCH WORDS

Unidirectional Rotating Bezel
An elapsed time rotating bezel, often found on divers' watches, that moves only in a counterclockwise direction. It is designed to prevent a diver who has unwittingly knocked the bezel off its original position from overestimating his remaining air supply. Because the bezel moves in only one direction, the diver can err only on the side of safety when timing his dive. Many divers' watches are ratcheted, so that they lock into place for greater safety. back to top

Universal Time
The mean solar time of the Greenwich meridian, counted from noon to noon, Often confused with the mean time notion. back to top

V - WATCH WORDS

Variation
In horology the term is usually referred to the variation of the daily rate, i.e. the difference between two daily rates specified by a time interval. back to top

Vibration Frequency (VPH)
The ring-shaped balance swings around its own axis and acts as the ruling organ of the movement’s escapement. Its amplitude (normally about 300 degrees) is restricted by the very thin balance spring, which also provides for the reversing of its direction of rotation. The frequency of the alternating vibrations is measured in Hertz (Hz) or in the more usual vibrations per hour (vph). Most of today’s wristwatches tick at 28,800vph (4Hz, like our own Malvern Automati ) or 21,600vph (3Hz). back to top

W - WATCH WORDS

Water Resistant or Waterproof
Usually measured in increments of one atmosphere (atm or bar, equal to 10 metres of water pressure) or metres and is often noted on the dial or case back. Swimming or snorkelling require 5 atm whilst scuba diving needs 20 atm to be sure. The record is held by The Hydromax by Bell & Ross which was developed for professional deep sea diving and is resistant to 11,100 metres! back to top

Wheel
Circular element, mostly toothed, combines with an arbor and a pinion to make up a gear. Wheels are normally made of brass, while arbors and pinions are made of steel. The wheels between barrel and escapement make up the so-called train. back to top

Winding Stem
Element transmitting motion from the crown to the gears governing manual winding and setting. back to top

Window
Aperture in the dial, that allows reading the underlying indication, mainly the date, but also indications concerning a second zone's time or jumping hour. back to top

World Time
Additional feature of watches provided with a GMT function, displaying the 24 time zones on the dial or bezel, each zone referenced by a city name, providing instantaneous reading of the time of any country. back to top

Z - WATCH WORDS

Zone
Small additional dial or indicator that may be positioned, or placed off-centre on the main dial, used for the display of various functions (e.g. second counters). back to top

Zodiac
Circular belt with the ecliptic in the middle containing the twelve constellations through which the sun seems to pass in the course of a year. back to top