Dan Read28 October 2013

Top Gear's A-Z of watches

Time to brush up on your horologist lingo

A

AUTOMATIC A mechanical watch movement, which is wound automatically by a pendulum swung by the physical motion of the wearer's wrist.

B

BEZEL The ring surrounding a watch's dial, typically with markings to indicate time zones, elapsed time or various other functions.

C

CALIBRE The model name of a watch's movement (similar to a car's engine code). It could be a number or a word, and varies by brand.

CHRONOGRAPH A watch that also includes stopwatch functions, to split time into intervals. Not to be confused with a chronometer (below).

CHRONOMETER A watch that has been officially tested at Contrôle Officiel Suisse des Chronomètres (COSC) to ensure its accuracy.

COMPLICATION Any function found on a watch beyond telling the hours, minutes and seconds (e.g. date, time zones, chronograph).

D

DIVING WATCH A watch designed to survive long periods underwater, while also indicating elapsed or remaining time to tell divers how much of their air supply remains.

E

ESCAPEMENT The ‘ticking' part of a mechanical watch that controls the energy released through the mainspring, and transfers it to the geartrain.

F

FLYBACK A type of chronograph that instantly restarts timing - zeroing the hands - when the wearer pushes a single button.

G

GMT A watch able to show time in two or more time zones (not just Greenwich Mean Time, as the name might suggest).

L

LUME Short for luminescent. Hands, numerals and markers may be coated with a lume material so that they glow in the dark.

M

MAINSPRING A spiral spring of metal, housed in the barrel, which - when wound -provides the source of power - or ‘fuel' - for a mechanical watch.

MANUAL WINDING A mechanical watch that must be wound by hand via the crown (usually found at the 3 o'clock position), typically once a day.

MANUFACTURE Always pronounced with comedy French accent: a watchmaker that builds its own movements.

MOON PHASE Device that shows the phases of the Moon via a subdial on a watch face. Realistically only of real use to sailors and werewolves.

MOVEMENT The ‘engine' of a watch. This could be mechanical or battery-powered, or a combination of both . If it's mechanical and automatic, it will be made up of the mainspring, barrel, geartrain, rotor, jewels, balance wheel and the escapement.

N

NOVELTY Swiss abuse of English, meaning ‘a brand-new model', though often they turn out to be novelties in the traditional sense...

P

PERPETUAL CALENDAR A function that shows the day of the week, date and month. Even compensates for leap years.

PILOT'S WATCH Usually oversized and designed for maximum legibility in the cockpit. Often features a GMT function and chronograph.

POWER RESERVE The amount of time for which a mechanical watch will run before it needs rewinding. Sometimes indicated on the dial, like a car's fuel gauge.

Q

QUARTZ A type of movement in which power - from a battery - is passed over a sliver of quartz crystal, which vibrates at a certain frequency. A computer divides this into minutes and seconds. The pulses also power the hands or an LCD display.

R

REPEATER A watch able to indicate the time via chimes, the most desirable being minute repeaters - originally developed so you can tell the time in complete darkness.

 

SAPPHIRE CRYSTAL The transparent cover of a watch face. Protects the dial and hands and, depending on quality, is highly scratch- and shatter-resistant. May also include a ‘cyclops' window to magnify the date display.

T

TOURBILLON A type of mechanical watch movement that counteracts the effects of gravity and other forces that affect accuracy.

W

WORLD TIMER Like a GMT function, but able to show all 24 of the world's standard time zones, often with names of cities from each zone featured.

 

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