Watch Acronyms: Every Abbreviation Decoded

Decoding Watch Jargon

Watch listings are full of abbreviations and acronyms. Here is a plain-English glossary of the ones you will actually encounter.

Movement Acronyms

• NH35: Seiko automatic, 3-hand date, 21,600 vph, 41h reserve — the modding standard
• NH34: Seiko automatic, GMT (4th hand), same base specs as NH35
• VK63: Seiko mecha-quartz chronograph — battery-powered time, mechanical stopwatch
• Miyota 9015: Japanese automatic, higher beat rate (28,800 vph), slimmer profile
• ETA 2824: Swiss automatic workhorse — the industry benchmark for decades
• Valjoux 7750: Swiss automatic chronograph — the most produced mechanical chrono ever

Spec Acronyms

• ATM: atmosphere — 1 ATM = 10m water resistance (3ATM = splash-proof, 20ATM = dive-rated)
• VPH: vibrations per hour — tick rate of the movement. 21,600 = 6 beats/sec; 28,800 = 8 beats/sec
• COSC: Contrôle Officiel Suisse des Chronomètres — Swiss accuracy certification
• AR: anti-reflective coating on crystal
• PVD: physical vapor deposition — case coating process for color and scratch resistance
• DLC: diamond-like carbon — premium black coating, harder than PVD
• FKM: fluoroelastomer — premium rubber strap material, UV and chemical resistant

Dial Terms

• Sunburst: radial brushed pattern that shifts color with light angle
• Guilloche: engraved geometric pattern, usually engine-turned
• Fumé: gradient effect, dark at edges, bright at center
• Tapisserie: stamped square pattern (popularized by AP Royal Oak)

Frequently Asked Questions

What does "in-house" mean?
A movement designed and manufactured by the brand itself, not sourced from a shared supplier.

What is a "homage"?
A watch that borrows design language from famous icons without copying trademarks — see our homage guide.

What is "NOS"?
New Old Stock — vintage watches that were never sold or worn, still in original condition.