Watch terms

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.

Bezel
The "ring" on the watch dial (or face) that holds the crystal in place. The bezel frequently describes the rotating ring around a diver or chronograph watch, which measures elapsed time.

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 strenous testing for timekeeping, stability, and quality by an independent testing agency.

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.

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.

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.

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.

Water Resistant
The ability to withstand water from entering. Terms such as "water resistant to 50 meters" or "water resistant to 200 meters" indicate that the watch can be worn underwater to various depths. However, no watch is fully 100 percent waterproof.