Watch terms, shown on the watch
The words collectors use, each one pointed out on the same watch: a chronograph from the front, an automatic movement from the back. Tap a part to see what it is called, or scroll down for the terms one by one.
Find it on the watch
Choose a view, then tap a part of the drawing or a word in the list. Only that part lights up.
From the front · tap a part or a term
Nothing selected yet. Try the crown.
The terms, one by one
In the order people usually learn them: the outside of the watch, the dial, the movement, and how it is finished. Where it helps, a button lets you see the thing happen.
On the outside
Case
The body of the watch. Its diameter is quoted in millimetres, but how it wears depends more on the lugs.
Lugs and lug width
The horns that hold the strap, and the gap between them: the number you need to buy a strap.
Crown
Winds the watch and sets the time. Pull one click for the date, two for the hands.
Pushers
The top pusher starts and stops the chronograph; the bottom one resets it to zero.
Crystal
The clear cover over the dial. Acrylic scratches but polishes out, mineral glass is harder, and sapphire is close to scratch-proof, though it can shatter.
Caseback
The lid on the back: snapped on, screwed down or held by screws. A glass one, called an exhibition caseback, shows the movement.
Thickness and lug to lug
Thickness runs from the top of the crystal to the caseback; lug to lug is the length from tip to tip. Lug to lug decides fit, and brands rarely publish it.
Strap or bracelet
A strap is leather, rubber or fabric, closed with a buckle or a folding deployant clasp. A bracelet is metal links, sized by adding or removing links.
Reading the dial
Hands
Hour and minute hands, read against the markers. Shapes have names: baton, dauphine, cathedral, Mercedes.
Sub-dials
Small dials inside the dial: running seconds at 9, elapsed minutes at 3, hours at 6.
Tachymeter
Time one kilometre with the chronograph; where the hand stops, the bezel reads your speed.
Hacking seconds
Pull the crown and the seconds hand stops, so you can set the watch to the second.
Inside the movement
Movement (calibre)
The engine inside the case. Brands name it by number, such as Sellita SW200 or Rolex 3235, and “calibre” means the same thing.
Mainspring and barrel
A coiled ribbon of steel stores the energy; the barrel is the drum that holds it. How long it runs once fully wound is the power reserve.
Gear train
The wheels that carry energy from the barrel to the escapement, each turning faster than the last. The fourth wheel turns once a minute and carries the seconds hand.
Escapement
The escape wheel and pallet fork release the train one tooth at a time. That release is the tick you hear, and each time it gives the balance a small push.
Balance wheel
The wheel that swings back and forth, the heartbeat of the watch. Each swing lets the hands move on by a fixed step.
Hairspring
The fine coiled spring that pulls the balance back on every swing. Most of a watch’s accuracy depends on it; silicon versions are unaffected by magnetism.
Frequency
How fast the balance swings. 4 Hz, or 28,800 beats an hour, is the modern standard; more beats make the seconds hand move in finer steps.
Amplitude
How far the balance swings each way, in degrees. Around 270–310° on a healthy, fully wound watch; well under 200° usually means it needs a service.
Jewels
Synthetic rubies used as bearings where the wheels pivot. An automatic usually has 25 or 26; more is not automatically better.
Bridges and main plate
The main plate is the base; bridges screw on top and hold the wheels from above. On fine movements their edges are bevelled and polished by hand.
Rotor
The half-moon weight that swings as your wrist moves. Each swing winds the mainspring a little; this is what makes a watch “automatic”.
In-house or supplied
A supplied movement comes from a specialist such as ETA, Sellita or Miyota and ends up in many brands’ watches. In-house means the brand makes its own, though how much is made under one roof varies.
Finishing
Brushing
Fine parallel lines rubbed into the metal in one direction. It gives a satin look and hides small scratches.
Polishing
Metal buffed to a mirror shine. Usually set next to brushed surfaces so the two contrast.
Bead-blasting
Fine beads fired at the metal leave an even matte grey. Common on tool watches and titanium cases.
PVD and DLC
Thin coatings, usually black, bonded onto the case. DLC (diamond-like carbon) is harder than most PVD, but both can chip on a hard knock.
Anti-reflective coating
A coating on the crystal that cuts glare, applied underneath, on top, or both. On top works best but wears over the years.
Sunburst dial
Fine lines brushed out from the centre, so a band of light sweeps across the dial as you turn your wrist.
Anglage
A bevel filed along the edge of a bridge and polished to a bright line. Sharp inward corners can only be done by hand, so collectors look for them.
Perlage
Small overlapping circles made with a spinning peg, usually on the main plate. Also called circular graining.
Côtes de Genève
Parallel waves ground across the bridges. Once said to trap dust, today mostly decoration.
Guilloché
Repeating patterns cut into a dial on a hand-turned rose engine. Stamped imitations look flatter and cost far less.
Blued screws
Steel screws heated until they turn deep blue. The colour also helps protect the steel from rust.
Engraving
Patterns or lettering cut into the metal, by hand or by machine. Look for it on solid casebacks and on bridges.