Watch Repair Glossary

Horology, or the study of time, has evolved with its own terminology over the millennia.

For example, the Tourbillon (French for “whirlwind”) is designed to increase a watch’s accuracy. Patented in 1801 by French-Swiss watchmaker Abraham-Louis Breguet, it’s essentially a rotating carriage device making one rotation per minute. When the watch’s balance, pallet and escape wheel are mounted in the tourbillon, the device averages any errors in the vertical positions.

Your Watch Service or Repair

For today’s customers having a watch serviced or expertly repaired, please ask us if about any terms you may not understand. We’ll gladly explain.

Here’s a small sampling of common terms you may hear in a discussion with one of our Timekeepers or Watchmakers.



A Synthetic material used to make a modern watch movement’s bearings – These synthetic Rubies are almost as hard as diamonds. The “Jewels” reduce friction and maintain the properties of the oil longer.

When the amplitude of a balance wheel exceeds 315 degrees, the roller jewel may strike the horn of the pallet fork at the end of the supplementary arc.

The angular distance which the roller jewel makes contact with the pallet fork.

The average, taken over one year of all the true solar days.

An imaginary line on the earths surface passing North – South in relation to the polar axis. In 1884, the 0 meridian was fixed as a line passing North – South through Greenwich Observatory in England.

Self compensating balance spring alloy, basically nickel steel containing beryllium and other additions.

Motion of balance from one position of maximum displacement to the next and the return to original position.

William Thompson

Life and Times

With an a Master of Fine Arts diploma in one hand and an Anthropology PhD in the other, William Thompson discovered a way to parlay his passion for mountaineering into a fascinating career as a photojournalist – using the camera lens as his ultimate “paintbrush.”

Thompson worked for 12 years with National Geographic, having created the first and only complete aerial coverage of Mt. Everest for the magazine. Other exotic assignments involved traveling via yak train through the Bhutanese Himalaya, living with pygmies in deep of Africa, and photographing the Asian elephant on its tragic path toward extinction.

His commercial image work includes major campaigns for Wells Fargo, Leo Burnett, Starbucks, Marlboro, Boeing, United Airlines, Intel, and Holland America.

Today, Thompson lives in a 90-year old log home near the waters of Puget Sound – and still finds adventure in climbing. Fee free to reach out to William via the following points of contact:

William Thompson Photograph/Film
15566 Sandy Hook Rd. NE
Poulsbo, WA