Journal · Glossary
The vocabulary, defined
Every term this site uses about a watch, in plain English, with the figures that make each one useful.
From the bench, Los Angeles · · 2 min read
A
- Amplitude
- How far the balance wheel swings, in degrees. Around 270 to 310 on a healthy movement; a falling amplitude is usually the first sign a watch wants servicing.
B
- Beat rate
- How many times a second the balance swings, quoted in beats or vibrations per hour. 28,800 A/h is eight a second and gives the sweep the eye reads as smooth; 21,600 is six.
- Bezel
- The ring around the glass. It may turn in one direction only (a dive bezel, 120 clicks), turn both ways, or not turn at all.
C
- Caliber, calibre
- The movement inside, named by its maker. The single biggest difference between two otherwise identical watches on this site.
- Cyclops
- The magnifying lens over the date on a Rolex crystal. Its absence or presence is a fast way to check a reference is what it says.
E
- End links
- The links that meet the case. Hollow end links rattle and date a bracelet instantly; solid ones are one of the things we check twice.
- Exhibition caseback
- A sapphire back through which the movement is visible. If a reference has one, the movement is part of what you are buying, which is the argument for a Swiss calibre.
L
- Lug-to-lug
- The distance from the tip of one lug to the other. It decides fit more reliably than case diameter does.
- Lume
- The luminous compound on hands and markers. Charged under light and photographed in the dark during inspection, for colour and evenness.
P
- Power reserve
- How long a fully wound movement runs untouched. Roughly 40 hours on older bases, around 70 on newer ones — the difference between a watch that survives a weekend off the wrist and one that does not.
R
- Rate
- How many seconds a day a watch gains or loses. Measured here over a full 24 hours in more than one position, and written on your film.
- Rolesor
- Rolex's name for a two-metal case and bracelet, steel with yellow, white or Everose gold.
S
- Service interval
- How often a mechanical watch wants stripping, cleaning and re-oiling. Five to seven years of regular wear is the honest figure.
- Super clone
- In this trade, a piece built to reproduce a specific reference closely enough to be measured against it rather than compared to it. It is what the grades on our pages describe.
T
- Taper
- How much a bracelet narrows from the case to the clasp. A bracelet that does not taper looks heavier than the watch is.
W
- Water resistance
- A rating in metres or ATM, measured in still conditions in a laboratory. Read it as a margin: 100 m is a shower and a pool, not a margin for working the crown underwater.
— The concierge desk, United Luxury