Glossary
Watch terminology used across this knowledge base, explained in one place.
Terms as used on Arvell datasheets. Alphabetical.
| Term | Meaning |
|---|---|
| ATM | Atmospheres of test pressure; 10 ATM = 100 m rating. See Water Resistance |
| Calibre | The specific movement model, e.g. Ronda R150 |
| Caseback | Rear cover; "exhibition" = sapphire window showing the movement |
| Chronograph | Stopwatch complication with start/stop/reset pushers |
| GMT | Second time zone shown by an additional 24-hour hand |
| Hacking seconds | Seconds hand stops when setting time - allows to-the-second setting |
| Jewels | Synthetic rubies used as low-friction bearings in a movement |
| Lug-to-lug | Case length between strap attachment tips - the key fit dimension |
| Lume / Super-LumiNova | Photoluminescent coating on hands and indices |
| Micro-adjust | Fine clasp length adjustment without removing links |
| Power reserve | Runtime of a fully wound mechanical movement (e.g. 40 h on the Ronda R150) |
| PVD | Physical vapour deposition - thin hard coating, e.g. black cases |
| Quartz | Battery-powered movement regulated by a quartz crystal |
| Quick-release | Spring bars removable without tools for strap changes |
| Sapphire crystal | Synthetic corundum glass, Mohs 9 - scratch-proof in daily wear |
| Screw-down crown | Crown that threads shut to seal against water |
| Small second | Seconds shown on a subdial instead of a central hand |
| Swiss Made | Legally protected designation for the complete watch - definition |
| Swiss Movement | Only the movement is Swiss - difference |
| Tapering bracelet | Bracelet narrowing from lugs to clasp |
| 316L steel | Corrosion-resistant, hypoallergenic stainless steel standard in watchmaking |
Sources: Arvell editorial (internal)
Last verified: 2026-08-25 · Last updated: 2026-08-25 · Maintained by: Arvell Watches - Brand Knowledge Team
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