AUTOMATIC Also known as self-winding, where the physical movement of the wearer's wrist winds the movement.
BEZEL The ring surrounding a watch's dial. Rotating versions have markings to indicate time zones, elapsed time or other functions.
CALIBRE Used as a term to describe and identify a watch's basic movement, eg ‘Breitling Calibre B01'.
CHRONOGRAPH A wristwatch that also includes stopwatch functions, to mark intervals of time.
CHRONOMETER A watch that has been fully tested at Contrôle Officiel Suisse des Chronomètres (COSC) to ensure its timekeeping according to tests for temperature, position, etc.
COMPLICATION Any function found on a watch beyond telling the hours, minutes and seconds eg date, moon phase, minute repeater.
DIVING WATCH A watch specially designed to survive long periods immersed in water, while also indicating elapsed or remaining time to tell divers how much of their air supply remains. Life-saving stuff...
FLYBACK A type of chronograph that instantly restarts timing when the hand is reset to zero.
GMT A watch able to show time in two or more time zones (not just Greenwich Mean Time after which this sort of watch is named).
MANUAL WINDING The watch has to be wound by hand, via the crown (usually found next to the 3 o'clock position), typically once a day.
MANUFACTURE Always pronounced with comedic French accent; it means a watch company that makes its own movements.
MOON PHASE Device that shows the phases of the Moon; only of real use to sailors and werewolves.
NOVELTY Swiss abuse of English. In watch parlance a brand-new model, though often - ironically - mere novelties in the English sense.
PERPETUAL CALENDAR A function that shows weekday, date, month as well as leap years.
PILOT'S WATCH Usually oversized, because they're designed for maximum legibility. Can also feature a chronograph and/or GMT functions. For time in the sky.
POWER RESERVE A device that shows how much time a watch will run before it needs to be wound again.
Quartz Instead of a mechanical ‘motor' powered by a spring, the resonant frequency of a quartz crystal - usually 32,768Hz - is used to regulate a battery-powered (or sometimes solar-powered) oscillator.
REPEATER A watch able to indicate the time via chimes, the most desirable being minute repeaters - originally developed so you could tell the time in complete darkness.
TOURBILLON A rotating cage containing the balance wheel, devised to counter the effects of gravity on pocket watches. Tricky to build, so found only in costly models.
TRIPLE CALENDAR A watch able to display the day, date and month.
WORLD TIMER Like a GMT (see G), but able to show all 24 time zones, with names of cities from each zone often featured.