Acrylic Crystal
An acrylic crystal is a less expensive alternative used in the mechanisms of the watch instead of a sapphire or a mineral crystal and comes in the form of a plastic composite. An acrylic crystal is more flexible and when subjected to impact it will flex as opposed to shattering. There is also less glare under bright light and scratches can be polished away.

Alarm
At a preset time the alarm is a function on the watch which either vibrates or makes a repetitive sound.

Altimeter
Most commonly found in the mechanisms of pilot watches, an altimeter is a function that displays information on the current altitude in response to changes in barometric pressure.

Analogue Watch/Display
A watch that displays the time with dials that have hands and numbers or markers. The usual analogue watch will present the time using a 12 hour display but some models also feature 24 hour analogue time.

Analogue-Digital Display
This is a watch which displays the time with hands and numbers or markers (see Analogue Watch/Display above) and also in digital format (a digital display). The analogue display section has a dial with hour, minute and sometimes second hands and the digital display shows the time numerically and sometimes with a liquid crystal display (LCD).

Annual Calendar
A watch that displays the day, date, month and 24 hours. This will automatically adjust according to months that are shorter and longer.

Aperture
This is a small opening located in the watch dial which usually displays the day or date.

Atmosphere (ATM)
The unit of pressure used when manufacturing the watch which indicates its level of water resistance. (1 ATM = 10 metres).

Automatic Movement/Winding
A mechanical watch whereby the wearer will physically wind the movement whilst wearing the watch instead of a manual mechanic which carries this process out automatically. As the wearer moves their wrist, a weighted rotor rotates and will wind the watches mainspring. Automatic watches have approximately 36 hours of power reserve and if it is not worn for a period of a few days it will wind itself down and it will be required to be wound by hand to get it started again.

Auto Repeat Countdown Timer
A countdown timer that will automatically reset and start the countdown again when the preset time has elapsed. It will continue to repeat the countdown until the wearer pushes the stop button.


Band
This is the general term used for the type of band or strap that attaches the watch to your wrist. Some watches have bracelet straps which are commonly made of metal and other bands may be rubber, polycarbonate or plastic.

Barrel
This is a cylinder shaped box in which the mainspring of the watch is contained. This barrel has a toothed or grooved rim which drives the main mechanisms of the watch.

Battery EOL Indicator
This stands for Battery End of Life Indicator and alerts the wearer to the imminent battery failure in a quartz watch. This is indicated when the second hand jumps in either two second or four second intervals.

Battery Life
For quartz watches this is the approximate indication of the time that the battery will continue to provide power to run the watch.

Battery-less Quartz
This is what is used for quartz hybrid watches whereby the power is generated by the electricity from the rotors inside the back of the mechanism. This electricity is stored in a capacitor or rechargeable battery as what you would find within a mechanical automatic watch, but with the increased accuracy of a quartz watch.

Bezel
This is the ring section or upper top part which surrounds the watch dial. The bezel is usually made of metal and can be embellished or set with diamonds or markings.

Bi-directional Rotating Bezel
This is a watch which has a bezel that can rotate clockwise and anti-clockwise to calculate speed and distance. On sports watches for example, the bezel may have calibrated markings and can rotate in one or two directions.

Bracelet
A bracelet is the term which refers to the metal band or strap attached to the main dial and secures the watch to the wearer�s wrist. If the bracelet is comprised of flexible separate links then these can usually be removed to adjust the length. Bracelets can be made of stainless steel, sterling silver, gold, titanium or a combination of all of these.


Calendar
The calendar function on a watch can refer to simply only showing the date in a cut-out window, through to a more complicated triple calendar showing the date, day and month. A combination of dial cut outs and pointer hands may be used. The most complicated calendar mechanisms may be mechanically programmed to show the year and months including those with less than 31 days; leap years can also be mechanically allowed for - this is referred to as a perpetual calendar.

Caliber
This is a term that is often used by Swiss watchmakers to describe or point out a particular model type. Caliber also refers to the watch movement's shape, layout or size.

Case
The outer metal housing that contains the internal parts of a watch. Stainless steel is the most common metal used, but titanium, gold, Stirling silver and platinum can also be used.

Clasp
This is the term referred to the attachment that connects, secures and fastens the watch band or strap on a watch bracelet. There are a few different types of clasps which depend on the strap, bracelet and watch type. These include butterfly clasps, fold over clasps, hook buckle clasps and a velcro clasp to name a few.

Chronograph
This describes a multifunction watch (most commonly a sports watch) which includes a stopwatch function. Most chronograph watches have either two or three sub dials, or mini dials, which measure the minutes and hours. Chronograph also has the ability to measure speed or and some can even time more than one event at a time.

Chronometer
A chronometer is used within a precision watch to test various temperatures and positions and meets the accuracy standards as set by C.O.S.C. in Switzerland. These watches are provided with a chronometer certificate with a unique test number detailing specific test results by the C.O.S.C.

Complication
This term refers to any feature in a watch that goes beyond just displaying the hours, minutes, and seconds. A watch that displays the hours, minutes, and seconds is usually known as a simple movement and complications include features such as moon-phases, second time zones and chronographs.

C.O.S.C.
This stands for the Control Officile Suisse de Chronometers (sometimes referred to as Swiss Controle Officiel des Chronometers) which is the independent Swiss regulatory organization that tests and certifies watch movements for chronometer status.

Countdown Timer
A function whereby the wearer can keep track of how much of a preset time period has run out. Some countdown timers also have a warning sound/signal a few seconds before the time elapses.

Crown
The crown is usually found in the form of a round piece of metal positioned on the right hand side of the case. The crown is used for winding the watch (if the watch is non-automatic), and also for setting the hands to the correct time and the date if the watch has this function. On diving/sports watches the crown may be screw-down where it screws onto a threaded tube. This then ensures that the watch provides higher levels of water resistance.

Crystal
The crystal is the transparent cover which is placed over the watch dial. There are three types of crystal often used. The first type is Acrylic crystal which is an inexpensive plastic that allows shallow scratches to be buffed out. Mineral crystal is made of a number of elements that are heat-treated to create an intense hardness that effectively resists scratches. Sapphire crystal is the most expensive and robust type of crystal is often used in conjunction with a non-reflective coating on some watches which prevents bright glare.

Crystal Skeleton Case back
This refers to a watch whereby the back of the case is made of a transparent material such as hardened mineral crystal or sapphire crystal. This then enables you to view the interior movements of the watch from the back.

Cyclops Lens/Window
A small viewable window or lens in the crystal that magnifies the date by approximately 2.5 times.


Day/Date Watch
A watch that displays the date and the day of the week.

Depth Alarm
An alarm features found on a divers watch that makes a repetitive sound to warn the wearer when the watch is submersed beyond a preset depth.

Dial
The dial which is also referred to as the face of the watch is the main visible area that tells the time. It is usually marked with numbers or accents which the hands point to. The dial also displays other functions such as chronograph sub dials. The dial can also feature special features or treatments such as mother-of-pearl finishes or guilloche.

Digital
A digital display shows the time in numbers instead of via hands on the dial. The numbers can appear in an LCD (Liquid Crystal Display), which shows a continuous reading or an LED (Light-Emitting Diode), which displays the time when a button is pushed.

Display
Indication of time or other data displayed either by hands pointing to the numbers or time markers on the dial (analogue display) or by means of numerals appearing in one or more windows (digital or numerical display).

Display back/Skeleton back
A transparent back section of the case which allows the interior watch movements to be viewed.

Divers Watch
Divers watches usually feature a graduated and rotating bezel which indicates the remaining oxygen levels. The watch will also feature a screw down winding crown, and must be water resistant to at least 200m or 660 feet of water. Divers watches are one of the most durable types of watches able to endure demanding physical environments.

Dual Time/Second Time Zone GMT Function
A watch which also displays a separate time zone via a sub-dial or an extra hand. The second time zone will usually be indicated as a 24 hour clock.


Ebauche
This is the basic movements of a watch whereby added complications or higher grade materials and components can be added.

Enamel
This is a substance with a translucent finish and when metallic oxides are added it forms different colours. When the enamel is heated it also develops into a consistency similar to glass and can be used to create a single colour on the dial or to create a pattern of mixed colours.

EOL indicator
This stands for Battery End of Life Indicator and is often indicated by the seconds hand which will jump every four seconds.

Escapement
This is the device found in a mechanical movement that controls the timing via the rotation of wheels and also the movement of the hands as a result of this. The escapement is what causes the ticking sound of the watch.

ETA
One of the most renowned and leading manufacturers of watch movements located in Switzerland. ETA movements are used by many major Swiss watch brands.


Face
The side of the watch (or the dial) that is visible and displays the numerals, hands, sub-dials, etc.

Fly back
The Fly back is an additional hand on a chronograph which moves with the second hand but can then be stopped on its own to measure an interval which can then "fly back" to catch up with the other hand. The Fly back function is often used to measure lap times whist also being able to measure the finish time.


Gasket
The gasket is the rubber or plastic ring that seals and protects the internal mechanisms of the watch against elements such as dust, water and moisture.

Gold Plating
This is an application of 18k gold over the surface of the watch case. Most watches that are gold plated are commonly made of stainless steel.

Gold, Rose Gold, White Gold and Yellow Gold
As pure 24k gold is too soft in consistency to make watches, it is therefore made into an alloy by mixing it with other metals. The portion or ratio of pure gold to other metals will then indicate the Karat rating. A moderate amount of copper in the alloy creates Rose Gold whilst a moderate amount of palladium and nickel creates white gold. The only natural form of gold is yellow gold.

Grande complication
This is a mechanical watch which comprises of a number of complications.

Guilloche
A type of decoration used in the watch dial for aesthetic appeal. Guilloche is often used on silver or silvered toned dials.


Hand
An indicator that points to the hours, minutes and is usually made of a thin and lightweight piece of metal.

Hand winding (Manual Mechanical)
A watch that has a manual mechanical movement which is required to be wound daily by the means of the winding crown. This then releases energy to power the watch.

Horology
The term used for the science and art involved in watch making.

Hunter-case
The case of a front covered pocket watch.

Half Hunter Case
This is the case of a pocket watch that has a circular shaped window cut out of the front cover. Most also have numbers on the cover that correspond to the numbers on the dial, meaning that the cover does not have to be removed.


Jewels
These are the synthetic rubies which act as bearings, end stones or pallets used to reduce friction within the movement of a watch. A large or increased number of jewels does not necessarily mean that the watch is of a better quality or more accurate.


Karat or K
This confirms the level of purity of the metal used which is indicated in the number of 1/24th of the pure metal used in the alloy.

Kinetic
This refers specifically to the Seiko line of Kinetic watches whereby the quartz hybrid movement that uses a battery recharges itself using the motion of the wearer�s wrist. Once the capacitor is fully charged, watches will store energy from between 3 � 14 days depending on the make and type of watch. The watch alerts you of low battery status when the seconds hand begins to move in two second intervals.


Lap Timer
A lap timer is a chronograph function that enables you to time sections of a race. At the end of a lap, the wearer will stops the timer which then returns to zero ready to commence timing the next lap.

LCD Display (Liquid Crystal Display)
An LCD display is found in a digital watch which shows the time electronically via a liquid contained in a thin layer between two transparent plates. The LCD uses less power than an LED (Light Emitting Diode) as the time is shown constantly as opposed to having to press a button.

Limited Edition Watch
A watch that is manufactured in limited quantities worldwide. The unique number of the watch is often displayed on the main body or on the caseback and will usually come with special packaging.

Lugs
Lugs are added extensions featured on either side of the case where the bracelet or strap is attached.


Mainspring
The mainspring is contained in the watch barrel and powers or drives the movement.

Manual Winding
This term refers to a watch which has a manual mechanical movement and will need to be wound on a daily basis using the winding crown. The winding motion releases energy from the mainspring to power the watch.

Mechanical Movement
This is a movement based on a mainspring, which when it wound slowly it evenly unwinds the spring which creates accurate timekeeping. Watches with mechanical movement incorporate the use of high-precision components.

Mineral Crystal
Mineral crystal is a type of crystal used in watches and is made from a form of glass. Mineral crystal is more scratch resistant than acrylic but if it does scratch however, it is difficult to polish and buffer out.

Minute Repeater
This is a complication on a watch that can strike the time in hours, quarters, or seconds with the use of a push piece.

Moon Phase
This is a complication on a watch which indicates the phases of the moon. One regular rotation of the moon around the earth is approximately every 29 days, 12 hours and 44 minutes.

Mother-of-Pearl dial
This is a pretty iridescent milky tone which is sometimes displayed on the watch dial and is the interior shell of the freshwater mollusc that is thinly sliced. Most mother-of-pearl dials will have a milky white tone but other colours such as silvery grey, grey blue, pink and black are also sometimes used.

Movement
The movement of a watch is the way it measures and keeps time or performs its functions. The movement is the combination of all the main mechanisms of the watch including the mainspring, escapement and the winding mechanism.


Perpetual Calendar
This is a watch which displays the date without manual adjustment, even in a Leap Year.

Platinum
Platinum is one of the most precious and valuable metals in the world and due to its strength, durability and weight it is a popular choice for setting high value luxury watches. Advantages of Platinum are also that it is hypoallergenic and tarnish resistant.

Power Reserve Indicator
This is a function on the watch that indicates how much battery power is left in a quartz watch. In an automatic watch, this is the power left in the main-spring.

Push-Piece:
A button that the wearer presses to work a specific function such as found on alarms and chronographs.


Quartz Movement
A type of watch movement that uses the vibrations of a small quartz crystal to measure the time. The power is sourced from a battery that should ideally be replaced every 2-3 years in standard quartz watches.


Ratchet Bezel
This is a type of bezel ring that can either turn in one way (unidirectional) or both ways (bi-directional) and also clicks when it rotates.

Register
The register is another term for a sub dial which is an extra dial positioned within the main dial of a watch.

Repeater
A repeater is a complication in a mechanical watch that when you press a specific button, will make a chiming sound to indicate the hours and sometimes the minutes.

Retrograde
This is the term used to describe a pointer hand on the watch dial and usually on a sub dial which automatically returns to zero at the end of a specifically timed period.

Rose (or pink) Gold
A red-hued toned gold that contains a combination of yellow gold with a mix of copper in the alloy.

Rotating Bezel
This describes a bezel that can be turned in one or two directions.

Rotor
The rotor is a flat piece of usually semicircular shaped metal and the part within a self-winding watch (automatic watch or quartz-hybrid watch) that winds the movement's mainspring. The rotor turns on a pivot with the motion of the wearers arm.


Sapphire Crystal
This is a synthetic sapphire used as the crystal of a watch. Sapphire crystal is incredibly scratch resistant and durable.

Screw-Down Crown
This is a type of crown on a watch that is screwed into a threaded barrel and increases the water resistant capabilities of a watch.

Self-Winding
A movement which is powered and wound by the movement of the wearer�s wrist as opposed to physically winding the watch as found in manual mechanical watches. Most automatic watches have up to 36 hours of power reserve and if not worn for one or two days, it will be required to be wound by hand to power up.

Shock Resistance
The level of impact that a watch is able to endure usually measured from various height levels.

Skeleton back/Display back
A case back which is transparent and thus allowing the interior watch movement to be viewed.

Split Second
This is a feature on a chronograph that is displayed via two hands; one which is a fly back and the other a regular hand. Split second time measurement is used to time laps or different finishing times the fly backhand can be stopped independently whilst the regular hand continues moving.

Stainless Steel
A highly durable metal alloy that will not be damaged by dust and rust and will not become discoloured or corrode.

Stopwatch
Found in a Chronograph watch, a stopwatch is where the seconds hand measures specific intervals of time.

Strap
The watch band which is commonly made of stainless steel, rubber, polycarbonate or leather.

Sub dial
This is a smaller dial displayed within the main dial and used for functions such as measuring elapsed minutes or hours on a chronograph watch, or to display the date.

Swiss A.O.S.C. (Certificate of Origin)
This is a mark identifying a watch that is assembled in Switzerland with Swiss components.


Tachometre (Tachymetre)
This is a function used alongside a chronograph that measures average speed or units usually in kilometres per hour and is often displayed on the watch bezel.

Titanium
A hard but lightweight metal which has a silver-grey toned appearance and is similar to stainless steel but 30 percent stronger and nearly 50 percent lighter than steel. Titanium has high resistance to salt water corrosion and therefore is often the chosen metal when making diver's watches.

Tonneau
This is a watch shape that has two convex sides.

Tourbillon
A tourbillion is a mechanical watch or clock escapement which counters the effects of gravity or other forces which may affect the accuracy of the chronometer. This is an extremely superior type of watch mechanism as it is incredibly difficult to make and is a highly valued complication in the watch making industry. It was invented by Abraham-Louis Breguet in 1801.

Train
These are a set of gears contained within the watch that are responsible for transferring the power from the mainspring to the escapement.

Twenty four (24) hour analog dial
This is found in a watch whereby the dial has an hour hand that makes one complete revolution, 360 degrees, in 24 hours. Twenty-four-hour analog watches are mostly used by pilots, scientists, and the military, and are often preferred as they represent the progression of a whole day.


Unidirectional Rotating Bezel
Most commonly found on divers watches, this is a type of bezel that moves only in an anti-clockwise direction and measures a specific period of time. Used as a safety feature for a diver, even if the bezel is moved off its original position the diver can still see their accurate remaining level of air supply.


Water Resistance
This refers to a watch that can endure low levels or splashes of water without any damage but isn�t geared towards swimming or diving. If a watch is designed to be worn underwater, it will display the maximum depth level in which it can be worn which is commonly referred to in meters or ATM (atmospheres).