Glossary of Terms: Watches, Watchmaking and Horology

Glossaries are listed alphabetically. Click on the letter-index below.

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Main Plate: - Base plate on which all the other parts of a watch movement are mounted (part of the "ébauche").
Mainspring: - The wound, flat metal spring which provides the motive power for the watch. Older mainsprings were "blue steel," but modern mainsprings tend to be made of alloys which are more resistant to breakage and corrosion. Most mainsprings for vintage pocket watches are currently out of production.
Manual Winding: - Refers to a watch with a manual mechanical movement, which needs to be wound by the wearer using the winding crown. This winds the mainspring up which then releases its energy to power the watch.
Meantime Screws: - Adjustable screws found on the balances of better-quality watches which are used to adjust the timekeeping of the watch without using the regulator. Also called timing-screws.
Mechanical Movement: - A movement based on a mainspring which when wound slowly unwinds the spring in an even motion to provide accurate timekeeping. As opposed to a manual mechanical watch which needs to be wound on a consistent basis, an automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist (see our section on automatic watch maintenance for more details).
Minute Repeater: - A watch which can additionally "repeat" the time, at the push of a button or move of a small slide on the side of the case, by striking the hours, quarter hours and minutes since the last quarter hour on small gongs inside the watch. See also "Repeater."
Motor Barrel: - An arrangement of the mainspring barrel in which the barrel is turned to wind the watch, and the barrel arbor turns as the watch runs down. This has the advantage that the barrel only has to turn when the watch is being wound, which allows the use of a longer and lower-powered mainspring. Motive power to the gear-train is provided by the turning barrel arbor. Also called a "safety barrel" because there is much less chance of doing damage to the watch if the mainspring breaks. In some higher grade watches the motor barrel is jeweled. See also "Going Barrel."
Movement: - The watch's "works." The mechanism of the watch, as distinguished from the outer case.
Nickel Silver: - A composition of nickel, copper and zinc often used in vintage watch cases. It contains no silver. Also known as German Silver.
Pallet: - That portion of the escapement which connects the time train to the balance, and allows the power of the watch to escape at a predictable rate through the locking and unlocking action of the pallet jewels on the teeth of the escape wheel. Also called the "jeweled lever".
Pendant: - The portion of the watch which holds the winding-stem and crown.
Pendant-set: - A watch that uses the pendant (stem and crown) to set the watch. See also "Lever-set". Also see our instructions on setting a pendant-set watch.
Pin Pallet: - A lever-escapement in which the pallet has upright pins instead of horizontally set jewels. Used in inexpensive "dollar watches" and mass-produced alarm clocks.
Pinion: - The geared arbor of a wheel which is "pushed" by a larger wheel.
Pivot: - The thin and usually fragile end of a moving axle or arbor which rests in the bearing or jewel.
Poising: - An operation to adjust the balance so that it doesn't have any "heavy spots" e.g. so that all weights on the balance are counter-poised.
Potence: - A small bridge which supports the lower balance jewels and the lower pivot of the balance in an 18-size watch.