Watch Terminology

 

 

 

The world of horology can be complex and even intimidating. Here are some terms in the watch industry to make you a more educated buyer and help you decide which options make sense for you.

A

 

ALARM:

A device that sounds a signal at a pre-set time.

 

ALTIMETER:

A device that determines altitude by responding to changes in barometric pressure.

 

ANALOG DISPLAY:

A term used to describe a watch that has hands versus a digital display.

 

ANALOG WATCH:

A watch with a dial, hands, and numbers or markers that present a total display of 12-hour time span. Analog digital refers to a watch that has both a digital display and hands of a conventional watch.

 

ANTI-MAGNETIC:

A watch that has been manufactured to resist becoming magnetized. (Watches that become magnetized may not keep accurate time because the magnetism interferes with the function of internal parts)

 

APERATURE:

Small opening. The dials of some watches have apertures in which certain indications are given (e.g. the date, the hour, etc).

 

AUTOMATIC MOVEMENT:

A mechanical movement that requires no winding because the rotor, part of the automatic mechanism, winds the mainspring every time you move your hand. Mechanical movements are accurate within one minute each day. Automatic movements have gained in popularity the last few years especially with watch connoisseurs and are considered to be Switzerland’s mechanical answer to the popularity of the no-winding-needed quartz movements that are standard in Japanese watches.

 

AUTOMATIC WATCH:

A watch whose mainspring is wound by the movements or accelerations of the wearer’s arm. On the basis of the principle of terrestrial attraction, a rotor turns and transmits its energy to the spring by means of an appropriate mechanism.

 

AUTOMATIC WINDING:

(also called “self-winding”) Winding that occurs through the motion of the wearer’s arm rather than through turning the winding stem. It works by means of a rotor that turns in response to motion, thereby winding up the watch’s mainspring. An automatic watch that is not worn for a day or two will wind down and need to be wound by hand to get it started
again.

 

B

 

BALANCE SPRING:

A very fine spring (also called a “hair spring”) in a mechanical watch that returns the balance wheel back to a neutral position.

 

BALANCE WHEEL:

The part of a mechanical watch movement that oscillates, dividing time into equal segments.

 

BEZEL:

The ring, usually made of gold, gold plate or steel, that surrounds the watch face.

 

BI-DIRECTIONAL ROTATING BEZEL:

A bezel that can be moved either clockwise or counterclockwise.

 

BRACELET:

A type of watch band made of elements that resemble links.

 

BRIDGE:

These are metal plates with “jewels” that hold rotating watch gears, much like columns between two floors of a building.

 

C

 

CALIBER:

A number and letter designation that identifies a watch model type. The term is also used to indicate the movement’s shape, layout, or size.

 

CASE:

The metal housing of a watch’s parts.

 

CASEBACK:

The reverse side of a watch case that lies against the skin. Most manufacturers engrave casebacks with their name, water and shock resistance, case metal content and other details.

 

CHRONOGRAPH:

A stopwatch, i.e., a timer that can be started and stopped to time an event. There are many variations on the chronograph. Some operate with a center seconds hand which keeps time on the watch’s main dial. Others use subdials to elapsed hours, minutes and seconds. Watches that include the chronograph function are themselves called “chronographs”.

 

CHRONOMETER:

This term refers to a precision watch that is tested in various temperatures and positions, thus meeting the accuracy standards set by an official institute in Switzerland. Most watch companies provide a certificate with your chronometer purchase.

 

COMPLICATION:

A watch with other functions besides timekeeping. For example, a chronograph is a watch complication. Other complications coveted by watch collectors include: minute repeater, tourbillon, perpetual calendar, or slpit second chronograph.

 

CROWN:

Button on the outside of the case that is used to set the time and the calendar, and, in the mechanical watches, to wind themainspring.

 

CRYSTAL:

The transparent cover on the watch face made of glass crystal, synthetic sapphire or plastic.

 

D

 

DAY/NIGHT INDICATOR:

A colored or shaded band on a world time that shows which time zones are in daylight and which in darkness.

 

DEPLOYMENT BUCKLE:

A type of buckle that pops open and fastens using hinged, often adjustable, extenders. Though more expensive than a belt-buckle like closure, a deployment buckle is easier to put on and remove and is more comfortable on the wrist.

 

DIAL:

The watch face. In high-end watches the numerals, indices and surface designs are applied as separate elements.

 

Dual Time:

A watch that measures current local time as well as at least one other time zone.

 

E

 

ESCAPEMENT:

Device in a mechanical movement that controls the rotation of the wheels and thus the motion of the hands.

 

F

 

FACE:

The visible side of the watch where the dial is contained.

 

FLYBACK HAND:

A second hand on the chronograph that can be used to time laps or to determine finishing times for several competitors in race. When reset, the second hand zips back to zero very quickly.

 

G

 

GASKET:

Most water resistant watches are equipped withgaskets to seal the case back, crystal, and crown to protect against water infiltration during normal wear. It is important to have the gaskets checked every two years to maintain the water resistance of the watch.

 

GEAR TRAIN:

The system of gears, which transmits power from the mainspring to the escapement. Some are made of solid gold to avoid magnetism, therefore making them more accurate.

 

GILT:

A layer of gold that has been electro-deposited onto a metal; its thinkness is measured in microns.

 

GUILLOCHE:

A style of intricate engraving that is popular on watch dials, usually very thin lines interwoven to create a surface texture.

 

H

 

HOROLOGY:

The study of time measurement, including the art of designing and constructing the timepieces.

 

I

 

INCABLOC:

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

 

INDEX:

An hour indicator on an analog watch dial, used instead of numerals.

 

ISOCHRONISM:

Meaning the watch runs at the same rate whether the watch is fully wound, or only partially wound.

 

J

 

JEWELS:

A bearing made of ruby or synthetic sapphires that act as bearings for gears in a mechanical watch, reducing friction and wear.

 

JUMP HOUR:

A watch that uses two dials instead of hands to shows the hour and minutes by means of a numeric window on the watch face.

 

L

 

LUGS:

Projection on the watch face to which the watch band/bracelet is attached.

 

M

 

MAIN PLATE:

Base plate on which all the other parts of a watch movement are mounted.

 

MAINSPRING:

The driving spring of a watch or clock, contained in the barrel.

 

MANUAL WIND:

A manual wind watch must be wound every day by the crown in order to run.

 

MECHANICAL MOVEMENT:

A movement based on a mainspring, which is wound by hand; when wound, it slowly unwinds the spring in an even motion. An automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist.

MOON PHASE:

A window in a watch face that shows the current phase of the moon is.

 

MOVEMENT:

The inner mechanism of watch that keeps time and moves the watch’s hand, calendar, etc. Movements are either mechanical or quartz.

 

P

 

PERPETUAL CALENDAR:

A calendar that automatically adjusts for the months’ varying length and for leap year.

 

POWER RESERVE:

The amount of energy reserve stored up to keep a watch running until it stops. The remaining power is sometimes indicated by a small gauge on the dial.

 

POWER RESERVE INDICATOR:

A feature of a mechanical watch that shows how much longer the watch will operate before it must be wound again.

 

Q

 

QUARTZ MOVEMENT:

A movement which allows a watch to keep time without being wound. This technology employs the vibrations of a tiny crystal to maintain timing accuracy.

 

R

 

ROTATING BEZEL:

A bezel (the ring surrounding the watch-face) that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions.

 

ROTOR:

A special weight in an automatic watch that rotates with the movement of the watch wearer and winds the movement’s mainspring.

 

S

 

SAPPHIRE CRYSTAL:

A crystal (the cover that protects the watch face) made of synthetic sapphire, a transparent shatter-resistant, scratch-resistant substance.

 

SCREW LOCK CROWN:

A crown that can be screwed into the case to make the watch watertight.

 

SHOCK RESISTANT:

A watch’s ability to withstand an impact equal to that of being dropped onto wood floor from a height of 3 feet.

 

SKELETON CASE:

A case with a transparent front or back that allows the wearer to view the watch’s movement.

 

SOLAR POWERED BATTERY:

Batteries in a quartz watch that are recharged via solar panels on the watch face.

 

STEM:

The screw pin connecting the crown on the right side of the watch case to the movement and used to wind the mainspring.

 

SUBDIAL:

A small dial on the watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on the chronograph, or indicating the date.

 

SWEEP SECONDS:

A seconds-hand that is mounted in the center of the watch dial.

 

T

 

TOURBILLON:

A device in a mechanical watch that eliminates timekeeping errors cause by the slight difference in the rates at which a watch runs in the horizontal and vertical positions.

 

TRITIUM:

An isotope of hydrogen that is used to activate the luminous dots or indices on a watch dial. The radioactivity released in this process is too slight to pose a health risk.

 

U

 

UNI-DIRECTIONAL ROTATING BEZEL:

An elapsed time rotating bezel, often found on divers’ watches, that moves only in a counter-clockwise direction.

 

V

 

VIBRATION:

Movement of a pendulum or other oscillating element, limited by two consecutive extreme positions. The balance of a mechanical watch generally makes five or six vibrations per second (i.e. 18,000 or 21,600 per hour), but that of a high-frequency watch may make seven, eight or even ten vibrations per second (i.e. 25,200, 28,800 or 36, 000 per hour).

 

W

 

WATER RESISTANT:

A water resistant watch can handle light moisture, such as a rain or sink splashes, but should not be worn swimming or diving. If the watch can be submerged in water, it must state at what depth it maintains water resistance, i.e. 50 meters or more on most sport watches.

 

WINDING:

Operation consisting in tightening the mainspring of a watch. This can be done by hand (by means of the crown) or automatically (by means of a rotor, which is caused to swing by the movements of the wearer’s arm).

 

WORLD TIME:

A dial, usually on the outer edge of the watch face, that tells the time up to 24 time zones around the world. The time zones are represented by the names of cities printed on the bezel or dial. Watches with this feature are called “world timers”.