The world of horology is filled with many terms. On top of that, watch aficionados seem to have their own lingo as well. We hope we can clarify some of this for you.

Adjusted: If a watch is ‘adjusted in 5 positions’ if it has been rated in at least 5 positions.

Amplitude: Maximum angle by which a balance swings from its position of rest.

Aperture: Small opening in the dial, such as the ones used for displaying the day and date. In “jump hour” watches the Aperture will be used for displaying the time.

Atomic watch: a watch which sets itself automatically via a radio signal from a centralized time keeping point

Automatic or auto: a mechanical watch which automatically winds when worn via a weighted rotor

Balance: On a mechanical watch, an oscillator that regulates the speed of the movement.

Balance Cock: A small bridge that secures the balance wheel with the movement.

Balance spring (hair spring): On a mechanical watch, a very fine spring that returns the balance wheel to a neutral position.

Balance wheel: On a mechanical watch, the part that oscillates, dividing time into equal segments.

Barrel: Thin cylindrical box containing the mainspring of a watch. The toothed rim of the barrel drives the train.

Beater: Junky watch or much-abused daily-wear watch.

Bezel: in all watches, the rim around the crystal that holds the crystal in. A rotating bezel is marked with information, such as time, world time cities, compass headings, or a slide rule, and does not function to hold the crystal. A rotating bezel can be external or internal.

Bridge(s): These are metal plates with “jewels” that hold rotating watch gears. Much like columns between two floors of a building.

Caliber: A term used to indicate the movement’s shape, layout, or size.

Caseback: The back side of a watch case (the side that lies against the skin).

Center seconds: a hand indicating seconds which rotates about the same axis as the minute and hour hands.

Chapter ring: a ring around the outside of the dial on which the hour and minute markings are printed or engraved.

Chronograph: a watch which includes a time counting function separate from the regular time, which can be started, stopped and reset at will.

Chronometer: The contemporary use of this word generally indicates a watch whose movement has received a rating certificate from a Swiss observatory. Earlier use of the word indicated a large, boxed marine timepiece which had a particular type of escapement and was very accurate.

Complication: a watch function which is in addition to regular time keeping. Technically a second hand is considered a complication, but since they are so ubiquitous, we usually don’t consider them as such. Popular complications include chronograph, alarm, second time zone, and power reserve.

crown (stem) (pin): The button on the outside of the watch case used to set the time and date. In a mechanical watch the crown also winds the mainspring. If the crown screws into the case (called a screw-in or screw-down crown), it makes the watch watertight.

crystal: The transparent cover on a watch face made of glass crystal, synthetic sapphire or plastic. High-quality watches typically have a sapphire crystal, which is highly resistant to scratching or breaking.

Deployment buckle: A buckle that pops open and fastens using hinged, often adjustable, extenders.

Desk Diver: a dive watch that is worn to the office and never used for diving

Ebauche: a movement in a rough, unfinished state. In the 19th century it referred to a movement provided to a watchmaker which was incomplete and needed to be finished. The word later took on the meaning of a finished movement provided to a watchmaker by a company specializing in movement manufacture.

ETA: one of the major Swiss makers of mechanical and quartz watch movements

Flip: WIS one-night stand, aka WIS catch-n-release

Flyback hand: A seconds hand on a chronograph that can be used to time laps or to determine finishing times for several competitors in a race.

Guilloche: A style of intricate engraving popular on watch dials.

Grail Watch: The single watch that a WIS aspires to, chases after, and seeks to own, above all others, i.e. a “Holy Grail”.

Hand-wind: a mechanical movement that needs to be manually wound to keep running.

Horology: The study of time and timepieces.

Incabloc: Shock absorber system used to protect a watch’s balance staff from breaking if dropped.

Jewels: pivot points in a watch made from synthetic sapphire. Prevents wear at the pivot points

Keeper: A favorite watch that will be kept, not traded or sold.

Lume: Luminosity; various materials i.e. tritium, luminova used to make watch faces “glow in the dark”.

Lugs: Projections on a watch face that attach the watch band or bracelet.

Main plate: Base plate to which the entire watch movement is mounted.

Mainspring: The driving spring of a watch.

Manufacture: the factory where the watch is made

Mechanical: a watch movement that keeps time with the power of a spring driving an escapement

Movement: The inner mechanism of a watch that keeps time and moves the watch’s hands and calendar.

N.O.S: an acronym for New Old Stock. Generally describes a watch that has been tucked away in some jewelers cupboard for years and years after the company that produces the model has gone out of business or no longer produces it in their model line-up.

Perpetual calendar: A calendar that automatically adjusts for the months’ varying lengths and for leap year.

Power reserve: Energy stored to keep a watch running; the power reserve indicator shows how much power remains.

Power reserve indicator: Shows when the watch will need a new battery or winding in the near future.

PVD physical vapor deposition: A gold-colored finish created with a coating of titanium nitrate covered by a coating of 22k gold.

Quartz: a watch that uses electricity and a quartz crystal to keep time. Usually battery powered.

Repeater: Chimes the time when a button is pushed.

Rotor: The part of an automatic mechanical watch that winds the movement’s mainspring.

Sapphire crystal: A crystal made of synthetic sapphire, which is transparent, shatter-resistant, and scratch-resistant.

Screw-down crown: a crown which threads onto the crown tube and securely screws onto it. Offers excellent water resistance for the crown.

Shock resistance: A watch’s ability to withstand an impact equal to that of being dropped onto a wood floor from a height of 3 feet (as defined by U.S. government regulation).

Skeleton case: A case with a transparent front or back, so the watch’s movement can be seen.

Spring bars (or pins): Spring-loaded bars used to attach a strap or metal bracelet to a watch case.

Super Luminova: a luminous material with strong lume properties and very long lasting. See Lumibrite (Seiko)

Sub-seconds: a hand indicating seconds which is in a small subdial separate from the main minute and hour hands.

Swiss made: A watch that is cased in Switzerland, contains a movement of Swiss origin, contains at least 50% Swiss parts, and passes its final inspection.

Tachymeter (tachometer): Measures the speed the wearer has traveled over a distance.

Tonneau watch: A watch shaped like a barrel, with two convex sides.

Tourbillon: A device that mounts the watch’s escapement in a small revolving cage to overcome the effects of gravity, allowing for precision in a mechanical watch.

Tritium: a luminous material that is mildly radioactive and is being replaced worldwide by Luminova.

Valjoux: a maker of watch movements, now owned by ETA. Famous for the 7750 automatic chronograph movement

Waterproof: No watch is fully 100 percent waterproof, and using the term waterproof is misleading and illegal.

Water resistance: The ability to withstand water. Terms such as ‘water resistant to 50 meters’ indicate that the watch can be worn underwater to a specific depth.

Winding: Tightening the mainspring of a watch by turning the crown (on an manual watch) or via the rotor (on an automatic watch).

WISease: a chronic disorder which strikes all who love watches. If you are not sure you have this, check the following to see if you can relate. If you can answer yes to at least two questions, you need to seek help!

World time dial: Usually located on the outer edge of a watch face, this dial tells the time in up to 24 time zones around the world. To use, check the scale located next to a city’s name and then add (or subtract) that amount from the local time.