The Terms Of Time

Analog Display Time indication by hands and a dial.

Applied Markers/Numerals Raised metal characters on a watch dial, usually at the hours of 12, 3, 6, and 9 only.

Arabic Numerals The figures 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Originated in India and introduced by the Arabs to Europe about the tenth century A.D.

Automatic Watch A mechanical watch with a mainspring wound by a wearer’s movement via a rotor. Also called a self-winding watch, as opposed to a manual-wind watch.

Bezel The frame around the case circumference in which the watch crystal is fitted.

Chronograph A watch that can act as a stopwatch to measure continuous or discontinuous intervals of time, from a fraction of a second to twelve hours.

Chronometer Not to be confused with a chronograph (although it can have one). A watch that has endured testing under extreme conditions. An official testing certificate accompanies each chronometer watch.

Crown The knob positioned outside of the case, usually at three o’clock, that is used to wind the mechanism and set and adjust the time.

Crystal The glass dial cover that fits into the bezel. It is made of either synthetic sapphire, which is virtually scratch-resistant; glass. which shatters easily; plastic, which scratches; or mineral crystal. a common medium.

Deployment Buckle Two curved and hinged metal plates on the watchstrap that conform to the wrist. When closing the buckle, one plate folds over the other for added security.

Dial The watch face that displays the hours, minutes, and seconds Some watches feature other smaller dials called subsidiary dials.

Digital Display A watch that displays time via digits rather than through a dial and hands display.

Greenwich Mean Time Mean solar time for the meridian of longitude at Greenwich, England, used as a basis for calculating time throughout most of the world.

Jewels Used as bearings at points of greatest friction in mechanical watch movements. The number of jewels is not generally indicative of the quality or value of the watch.

Lug Part of the watchcase to which a bracelet, band, or strap may be attached.

Mainspring The principal spring in a watch.

Mechanical Watch A watch that derives its energy from a spring mechanism wound manually or automatically.

Minute Repeater A watch that chimes the hours, quarter hours, and minutes with the push of a button. There are also quarter and five-minute repeaters.

Moon-phase Watch A watch that displays the various phases of the moon in a crest-shaped window.

Movement The complete mechanism within a watch – whether quartz or mechanical.

Pave Meaning “paved with,” as in a dial, bracelet, or bezel with precious stones.

Perpetual Calendar A watch with a counting instrument that tracks the number of days, taking into account 30- and 31-day months and leap years.

Power Reserve Indicator A mechanical-watch feature that shows how long the watch will run before it must be wound again. Quartz watches often have a battery reserve indicator. which informs the wearer when the battery is low on power.

Quartz Watch A watch that derives its energy from a miniature battery, which may last several years. The time kept by a quartz watch varies less than one second per day.

Roman Numerals The numeric symbols I, II, III, IV, and V. Commonly used on watch dials in place of Arabic numerals.

Rotating Bezel A bezel that can be rotated to perform a variety of functions. Unidirectional bezels turn in a counterclockwise direction. A popular feature on diving watches.

Rotor The device that winds the mainspring in automatic watches.

Sapphire Crystal Scratch-resistant crystal made of synthetic sapphire.

Scratch Resistance A watch’s ability to withstand scratching and scraping on its bracelet, case, or crystal. While other countries may use the term scratch-proof, it is an illegal term in the United States.

Screw-down Crown A crown that screws into the watchcase and secures the watchcase from potential water intrusion.

Shock Resistance A watch’s ability to withstand an accidental fall onto a hardwood surface from a height of three feet without being damaged. In the United States, no watch may legally be called shock-proof.

Skeleton Watch A watch with a see-through or cutaway dial, showing the interior mechanism.

Subdials Additional watch face dials that indicate functions such as moon phases, second time zones, or day and date.

Tachymeter (or Tachometer) A function on the bezel that measures the speed at which the wearer has traveled over a measured distance.

Tank Watch A rectangular case. Originally an exclusive name for a Cartier wristwatch. which was inspired by the tracks of a military tank.

Titanium An understated space-age white metal that is 50 percent lighter and 50 percent stronger than stainless steel, and nonallergenic.

Tonneau Case A case with a barrel shape (a wide center and flat, tapered ends).

Tourbillon Invented by Abraham-Louis Breguet, this watch nullifies timekeeping errors caused by slight differences in the watch’s running rate in the horizontal and vertical positions.

Tritium Glow-in-the-dark paint (for hands, dials, and markers on the watch dial) that aids legibility in the dark.

Water Resistance A watch’s ability to withstand the potential effects of water contact to varying depths – from mild splashes to underwater depths up to 200 meters or more. Divers’ watches feature greater water resistance.

Multi Time Zone A watch that displays the current time in any chosen city or time zone. The city names are often on the outer edge of the dial.