Watch Education

Glossary

Automatic Movement

A movement that is all mechanical and requires no winding because the rotor (part of the automatic mechanism) winds the mainspring by the movement of the wearer's arm. Most mechanical movements are accurate within one minute each day and have reserve power when not worn of at least 24 hours. Often used interchangeably with the word caliber.

Battery

A device that converts chemical energy into electricity. Most watch batteries are silver oxide type delivering 1.5 volts.

Bracelet

A flexible metal band consisting of links in a similar style as the case. The bracelet size can be adjusted by removing links from the bracelet.

Carat (karat)

Refers to the fineness of the gold and gemstone weight. For example, pure gold is 24k. 18k gold is 75 percent pure.

Case back

The bottom of the watch case that covers the movement.

Chronograph

A multifunction watch with a stopwatch function. Most have two or three smaller dials for measuring a period of time without affecting the main time display.

Chronometer

Usually refers to a Swiss-made watch that meets very high standards set by the Swiss Official Chronometer Control (C.O.S.C.). A Swiss watch labeled a chronometer has a mechanical movement of the very highest quality and the movement has undergone strenuous testing for timekeeping, stability, and quality by an independent testing agency.

Complication

Highly prized and almost always a signal of a complex, expensive movement, a complication refers to an additional mechanism(s) in a watch movement. Examples of complications include chronographs, perpetual calendars, and moon phase displays.

Crown

Small pin, button, or knob extending from the case that is used to set the time and date. Water-resistant watches feature crowns which screw into the case.

Crystal

The transparent cover over the watch face. It is usually made of glass, acrylic crystal, mineral crystal, or synthetic sapphire. The latter is the most expensive and durable, approximately three times harder than mineral crystal and 20 times harder than acrylic crystal. Sapphire crystal is highly resistant to scratching or shattering.

Dial

The dial refers to the face of the watch.

Hidden Deployment Clasp

A hidden deployment clasp is invisible when it is being worn. The ends of the bracelet come together to meet so that none of the clasp shows. Also known as a push button clasp, it is used to secure a bracelet on better quality timepieces. To release the clasp you simultaneously depress the two buttons on either side of the bracelet.

Jewels

Synthetic sapphires or rubies that act as bearings for gears of a mechanical watch. The jewels reduce friction to make the watch more accurate and longer lasting. A quality hand wound or automatic mechanical watch contains at least 18 jewels -- many more, if the watch features complications.

Manual

A hand-wound mechanical watch; when wound, it slowly unwinds the mainspring in an even motion. An automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move.

Lugs

Projections on a watch face that attach a watch band or bracelet to the dial.

Luminous

Usually refers to dials which are partly painted with luminous salt so they can be seen at night.

Moon Phase

An indicator that keeps track of the phases of the moon. Once set, the moon phase indicator accurately displays the phase of the moon, which rotates around the earth once every 29 days, 12 hours, and 44 minutes.

Quartz

A natural or commercially synthesized silicon dioxide rock crystal. When activated by a battery or solar power, the thin sliver of crystal very predictably vibrates at an extremely high frequency thus providing very accurate time, with a degree of accuracy that deviates no more than one minute a year.

Sapphire

A synthetic crystal with a hardness second only to diamond. Transparent sapphire is used for scratch-proof watch dial covers.

Shock Resistance

As defined by the U.S. government, a watch is considered shock resistant if it can withstand an impact equal to that of being dropped onto a wood floor from a height of 3 feet.

Skeleton Case

A transparent or partially transparent front or back that enables parts of the inner watch to be seen.

Swiss Made

According to Swiss law, a Swiss-made watch means that at least 50% of the parts are Swiss made and that the assembly, finishing, and final inspection occurs in Switzerland.

Tachymeter

A measuring system on the outer bezel that is used to measure speed.

Water Resistant

In our experience, the ISO water guidance classifications are too liberal and we believe it is better to be safe than sorry.

Water resistance 50 meters (165 feet): It is wearable while playing sports. It should not be worn in or around water or even around household sinks. Wearing the watch in light rain is fine.

Water resistance 100 meters (330 feet): It is wearable around household sinks, while playing sports or taking showers, and in shallow water. It may be suitable for swimming, surfing, snorkeling, or poolside diving, depending on the brand. Some brands, especially those with a strong aquatic, diver orientation--such as Rolex, Omega, Luminox, and Tissot--have better reputations for water resistance and should be fine for these activities. Regardless, a watch with water ressistance 100 meters (330 feet) should not be worn while scuba diving.

Water resistance 300 meters (990 feet): It is wearable around household sinks and while playing sports, swimming, surfing, snorkeling, poolside diving, and scuba diving at depths not requiring helium gas. That said, most manufacturers recommend watches with 300 meters (990 feet) water resistance have their diving watch pressure tested and seals replaced by an authorized service and repair facility every two to three years