This is a repost from http://www.watch-next.com/watch-words-mea
The world of timepieces has its very own language that to an outsider can appear confusing. For example the difference between a chronograph and a chronometer. Here’s a guide to some of the most commonly used words.
A watch that displays the time using hands that rotate around a dial, the latter usually marked with hour and minute indications.
A watch that indicates not just the day, date and month, but self-adjusts for short and long months – sometimes with just one annual correction.
A mechanical as distinct from quartz (battery powered) watch that winds itself thanks to a rotor activated by the movement of your wrist. Keep moving and it will stay wound.
The wheel in every mechanical watch that swings to and fro to keep things ticking.
The circular receptacle that contains a mechanical movement’s coiled mainspring.
The ring on the face of the watch, fixed or rotatable, that “frames” the crystal. Rotating bezels can be turned to indicate time intervals.
The metal plate that provides a supporting framework for bearings and moving parts of a watch’s movement.
A name for the power-unit or “machinery” driving a watch.
The topside of a watch’s exterior that houses the workings.
The rear of the case that screws or snaps off for access to the mechanicals or module. Increasingly crafted in sapphire crystal so you can see what’s inside.
An invention by English watchmaker George Daniels further developed by Omega. By reducing friction in a movement it promises enhanced accuracy and longevity.
A watch with a stopwatch function that measures elapsed time, and can be used to time something, for example, a sporting event or lap time.
A rating given to watches that according to the Swiss Official Chronometer Control (C.O.S.C.) are accurate to minus 4 or plus 6 seconds a day.
Refers to one of two common types of chronograph mechanisms, the other being a simpler lever-and-cam system.
The watch world's name for the watch glass – whether it’s the now-common sapphire crystal or acrylic.
Secures the watch strap or bracelet: commonly a pronged buckle or a hinged or butterfly-like fold-over “deployant” device.
Functions a watch provides in addition to the time: from a simple date or stopwatch function to perpetual calendars and tourbillons.
“Côtes de Genève”
A traditional “striping” decoration or finishing on the polished metal surface of a watch movement.
The protruding and often grooved knob, usually on the right side of the watch case, for winding and time adjustment.
The watch face.
A watch that displays the time using numerals rather than hands, most common with quartz timepieces.
A watch capable of water resistance to plus 200 meters, usually featuring a rotating bezel to mark dive-times. Serious versions have a screw-down crown and caseback and often a helium release valve, even in some cases a depth gauge.
Dual Time Zone
A watch that displays both local time – the time where you happen to be, and home time, the time back home.
The basic mechanical watch movement before final assembly.
Equation of time
A feature that calculates and indicates the difference between solar time and standardized
A Vital part of the movement that regulates the release of the energy generated by the mainspring, thus ensuring the balance wheel oscillates evenly.
A system that lets you stop and restart the stopwatch function with just one press of the start button.
The initials representing Greenwich Mean Time. Also describes a timepiece that can indicate times in multiple time-zones.
A hand or engine-powered engraving method that decorates dials or parts with fine interlaced lines.
A watch that allows time-setting to the second via a crown that stops the movement when pulled out.
Synthetic jewels used as low friction bearings in a mechanical movement.
The display of hours in digital form with the next hour “jumping” into view on the hour, while minutes are displayed with the traditional minute hand.
The horn-like extensions on a watch case that secure the strap or bracelet.
A mechanical movement you have to wind by hand.
A watch that chimes the hours, quarter-hours and minutes at the press of a button.
A watch with a miniature moon face that changes position to indicate the position of the moon in the sky as the month passes.
The mechanism that drives a watch: traditionally mechanical, automatic or hand-wound, or quartz, kinetic or solar driven.
A watch that indicates the day of the week, the date, the month and the phases of the moon for an up to 400-year cycle.
Refers to how long a watch will continue running after being fully wound or activated.
A battery powered quartz crystal module that’s used as an alternative to traditional mechanical movement.
Refers to watch hands that complete an arc, for example from 0 to 31 for a date indication, and then automatically spring back to the starting point before recommencing their trajectory.
A semicircular metal balance that swings freely to wind the mainspring in a self-winding mechanical watch.
The cutting away of parts of a watch, from movement to dial, to reveal the inner workings.
A stop-watch mechanism with super-imposed seconds hands that can be used independently for split or lap timing.
A complex module originally designed to counter the effects of gravity on pocket watch mechanisms, now employed for accuracy and to demonstrate high-end craftsmanship.
The wheels and pinions that connect the main parts of a watch movement.
The frequency a mechanical movement operates at. Usually, the balance vibrates or swings to and fro at six or eight vibrations a second, expressed as 3 and 4 hertz, translating to 21,600 or 28,800 vibrations per hour. (The higher the hertz, the greater the accuracy.