Glossary of Timepiece / Watch Terminology.
The terminology surrounding watches is often familiar but the specific meaning may not be fully understood. The aim of this glossary of watch terms is to provide just enough information to help in understanding the descriptions of watches offered for sale.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Accuracy: A confusing term, as a watch that consistently looses or gains the same amount of time each day can be referred to as accurate because it functions at a consistent standard. Ideally an accurate watch will be consistent with telling the 'real time' day after day without the need for adjustment.
Acrylic Crystal: The 'Crystal' is the cover that protects the watch dial. An acrylic crystal is basically plastic. The benefit being it flexes rather than shatters on impact, is easily polished allowing scratches to be buffed out and produces little glare under bright light. Acrylic is less expensive compared to a sapphire or mineral crystal.
Altimeter: An instrument that registers altitude above sea level by responding to changes in barometric pressure.
Analogue (Analog) Watch: A watch that displays time using hands and a 12hour dial. A term from the world of electronics that was adapted into the world of watch making as the quartz movement became more widely used.
Antimagnetic Watch: A watch whose parts are protected from but the very strongest magnetism; quartz watches are not troubled by magnetism.
Annual Calendar: Function showing the day, date or month or a combination.
Aperture: A small opening in the dial. Example an aperture allows for the display of the date.
Applied Numerals: Raised characters attached to the dial face.
Atmosphere (Atm): A unit of pressure that equals the pressure of the atmosphere at sea level. ATM indicates how water resistant a watch is and what depths it will withstand.
Automatic, Automatic Movement / Automatic Winding: A watch that does not require hand winding. Automatic usually refers to mechanically powered watches which self wind as a swinging mass or rotor turns (which rotates by arm movement) and then through a series of gears, winds the mainspring which in turn powers the watch. Most automatic watches can reserve up to 36 hours of power meaning if it is not worn for a day or two they will wind down requiring hand winding to get it started again.
Auto quartz: See Battery-less Quartz
Auxiliary Dial: A small dial set within the larger dial face that shows seconds only.
Back Winder: Flat crown (winder - for setting time and winding) that is set into the back of the case.
Baguette: Rectangular shape, normally with a length at least three times its width.
Balance: Refers to the running regulator of a mechanical watch which oscillates about its axis of rotation. A hair-spring makes it swing back and forth in equal time parts. Tick-tock. Modern wristwatch balances can beat up to 10 times per second.
Band: The band holds a watch on your wrist. The main types being bracelet and strap,
Barrel: The circular box housing for the mainspring.
Baton Numerals: Simple stick like non-numerical markers which most commonly show the minutes on a dial but also may be used to show hours.
Battery: A small device which converts chemical energy into electricity. Silver oxide batteries deliver 1.5 volts while the longer-lasting lithium batteries deliver 3 volts.
Battery EOL - End Of Life: The Battery End Of Life indicator serves to forewarn of approaching battery failure within the next week or two. In a quartz watch this is usually seen as a change in the movement of the second hand as it starts to jump in 2 or 4 second intervals.
Battery Life: Simply how long a battery will continue to provide power.
Battery-less Quartz: A variation on the automatic watch in which the rotor movement generate an electric current that is stored in a capacitor or rechargeable battery. These watches also need to be worn on a regular basis in order for their electric power reserve to be maintained. Various makers use specific terms for such watches. Eg. Kinetic (Seiko), Omega-matic (Omega), and Auto quartz (Invicta).
Bezel: The bezel is the topmost ring that surrounds the watch dial and is set around the outside of the crystal fitting it in place. Can be either fixed or rotating as on divers watches. in the case of a diver's watch, rotating. Bezels may be plain, marked with a 0-60 minute scale or even diamond set.
Bi-directional Rotating Bezel: A bezel that rotates in either a clockwise or counter clockwise direction.
Bracelet: A bracelet generally refers to a flexible metal band made up of interconnecting links which can be detached from each other to adjust the band length.
Breguet Hand: AKA - moon hand. Popular design by Breguet; the slightly tapered needle of the hand ends in a pointed head mounted on a circle, which is pierced with a hole.
Blued Screws: A traditional decoration practice rather than functional requirement in high quality movements which were fitted with screws that were artificially blued.
Button: Most commonly called the winder by the general public. The Crown is the common industry term.
Cabochon: A Cabochon is a smooth round or oval convex shaped polished gemstone. A Term often encountered when a decorative stone set in the watch crown is being described. I.e. Cabochon Crown - Crown or winder set with a cabochon jewel.
Calendar: The calendar mechanism or function on a watch can consist of a date only showing in a window through to a 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 that 31 days; leap years can also be mechanically allowed for. Sometimes referred to as perpetual calendars.
Calibre: Traditionally used to indicate the diameter of a watch movement. These days it often just refers to the type of watch. (e.g. ladies, automatic)
Carat: See also Karat The official scale of gold purity. Eg. 24 carat signifies pure gold, 18 carat has a lesser quantity of gold.
Case or Watchcase: The usually metal housing that contains the internal parts of a watch. The most common metal used is Stainless steel. Titanium, gold, silver and platinum are often found in high-end watches.
Chronograph: - DO NOT CONFUSE WITH CHRONOMETER! A chronograph function measures short time spans independently of the normal timekeeping function. Normally the mechanism is indicated by the presence of one or more subdials. Various watches incorporate different functions and can measure seconds, minutes or hours. A stop watch is the term that best describes a chronograph function as it functions independenatly of the normal time keeping of a watch and can be started and stopped without affecting that function. Other chronograph functions include determining speed or distance and even measure more that one thing at a time (see also tachometer, telemeter, flyback hand & split seconds hand).
Chronograph Rattrapante: The addition of a flyback hand (rattrapante) allows the measurement of split second times or timing simultaneous events of unequal duration.
Chronometer: This term refers to specific timekeeping standards criteria laid down by the Swiss Official Chronometer Control (C.O.S.C.) . Tests are conducted at various temperatures and in various positions out of the case for 15 days & nights. Watches that pass the standard are provided with a chronometer certificate that details the specific test results. Clasp: The clasp connects the two ends of a watch bracelet.
Complicated Watch: A watch that has other functions that do not directly relate to the time of day. (eg: calendars, chronographs, moonphases, perpetual, repeaters etc..)
C.O.S.C.: Swiss Official Chronometer Control, Control Officile Suisse de Chronometers or Swiss Controle Officiel des Cronometres- the independent Swiss regulatory organization that rigorously tests and certifies (or fails) watch movements for chronometer status.
Countdown Timer: A function that tracks how much time has elapsed out of a set period. Some countdown timers have the added function of sounding a warning a few seconds before the time runs out.
Crown: Commonly referred to as the winder or even knob, as it was the original method used for winding a watch. The crown is also used to set the hands to the correct time and date. On diving/sports models, the crown may be screw down whereby it screws onto a threaded tube which protrudes from the case of the watch. This often ensures superior water resistance. The crown is most commonly set at the 3 o'clock position.Crystal:The clear cover over the dial, (AKA - the glass) which fits into the bezel. Various materials including acrylic/plastic, mineral (glass - quartz crystal) and sapphire. Mineral crystal is composed of several elements that are heat-treated to create an unusual hardness that aids in resisting scratches. Sapphire crystal is the most expensive and durable, approximately three times harder than mineral crystals and 20 times harder than acrylic crystals. A non-reflective coating on some sport styles prevents glare.
Crystal Skeleton Case: A transparent case back (or front) made of mineral or sapphire crystal that allow the intricate movement of the watch to be viewed
Cyclops: A small magnifying window or lens set in the crystal to magnify the date.
Day/Date Watch: A watch that shows the day of the week as well as the date.
Decorated Movement: While not directly related to improved function it indicates a degree of hand assembly/finishing and an attention to detail in watch construction. To show off such decorated movements a Crystal Skeleton Case is often used.Deployment Buckle (Foldover): The three-folding closure of a bracelet band.
Depth Alarm: An alarm that can be preset to sound when specific depth has been reached.
Depth Sensor/Depth Meter: A device that measures water pressure to determine the wearer's depth. On a divers watch a scale on the dial indicated by analogue hands or a digital display.
Dial: The dial, or the face, is the surface of the watch marked with numbers or batons indicating hours and minutes. Dials of chronographs can apperar very complicated when set with several subdials. The dial is often the point of difference from a decorative aspect. Digital: The display of time in numbers either as an LCD (Liquid Crystal Display), which shows a continuous reading or an LED (Light-Emitting Diode), which shows the time at the push of a button.
Display: Refers to the indication of time or other data, either by means of hands moving over a dial (analog display) or by means of numerals appearing in one or more windows (digital or numerical display).
Diver's Watch: Traditionally feature a graduated rotating bezel and often a screw down winding crown. Minimum water resistant for a divers watch is to 200m. A diver's watch must confirm to specific standards. See also Water-resistant.
Dual Time/Second Time Zone Bezel: A watch that can measure both current and one other time zone. A rotating bezel, twin dial, extra hand, subdial, or other means may be used to display the secondary time zone.
Duoplan or Duodial: A doctors or nurses watch with an auxiliary seconds dial sperate from the hour and minute dial used for when taking a pulse.
Ebauche: The ebauche is the basic movement of a watch.
Elapsed Time Rotating Bezel: A graduated rotating bezel used to keep track of periods of passed time. The bezel is simply turned by the wearer to align the zero on the bezel with either the second or minute hand allowing the elapsed time to be read off of the bezel.
Engine Turning: Decorative engraving.
EOL - End of Life: The end of battery life. See - Battery EOL - End Of Life:
Escapement: The combination of parts including the anchor, pallets and balance wheel amongst others in a mechanical watch which translate the power of the mechanism into regular timekeeping. The escapement is the source of the ticking sound of a mechanical watch.
Face: The visible front surface of the watch AKA the dial.
Flyback: A term that can be used to describe two different functions of a chronograph watch. Some use it to describe the function of depressing a chronograph button which returns the seconds hand to zero but immediately starts the timing again. Also (probably wrongly) used to describe the split seconds chronograph which has two seconds hands sitting atop one another. An additional hand on a chronograph which moves with the second hand but, can be stopped independently to measure an interval which can then "fly back" to catch up with the other hand. This is useful for capturing lap times without losing the ability to capture the finish time. On depression of a third chronograph button (most have two), the flyback hand will stop in order to measure say, a lap time; repressing this button with cause the flyback hand to flyback(!) to the other seconds hand which has remained in motion.
Foldover Buckle: (Deployment): A three-folding enclosure that secures the two ends a bracelet band.
Form Watch: Watch in a very unusual shape.
Frequency Amplitude: in mechanical watches this refers to how many times each hour the watch ticks. It is often referred to as half-swings per hour or beats per hour (BPH). a watch beating at 8 times per second has amplitude of 28,800 ticks per hour.
Gasket: The seal, usually a rubber or plastic ring used to protect the internal mechanism of a watch against dust, moisture and water.
Gear Train: In a mechanical watch the gears which run from the mainspring to the escapement which converts power into timekeeping.
Geneva Stripes: A stripe decoration on the movement plates seen in high grade watches.
GMT Timezone: GMT (Greenwich Mean Time), also known as Zulu Time. Refers to the time of the international clock in Greenwich, England.
Gold Plating: When a layer of gold is applied over the surface of another material.
Gold, Rose Gold, Yellow Gold, and White Gold: Yellow gold is the natural form of gold. Pure gold is very soft so it is normally mixed with other metals to form an alloy. The Carat (Karat) rating signifies the proportion of pure gold to other metals in the alloy. 24K is pure gold. 18K is 75% pure. Various colours result depending on the other metal in the alloy. Copper creates Rose while palladium and nickel creates white.
Guilloche: A dial decoration that gives the dial great depth.
Hack Features: Balance stopping – The second hand is stopped by pulling out the crown (winder) to enable the synchronizing of time with another timepiece.
Hand: The time Indicator that rotates around the centre point of the dial. Normally watches have three hands to show the hour, minute and seconds.
Hand winding(Manual Mechanical): A watch that must be wound by the crown. This action winds the up mainspring which then will release energy to power the watch as it releases.
Incabloc: Incabloc is a trade name for a type of shock absorbing device/spring used to protect the delicate parts of the mechanical watch escapement.
Index/Indices: The dial markings that represent the hours and minutes.
Integral Bracelet: A bracelet band that appears to be a natural extension of the watch case.
Jewels: Refers to the bearings required in a watch where movements are subject to constant motion and friction in order to reduce wear and maintain the precision of the timepiece over a long period. Most commonly synthetic rubies are used. More jewels do not necessarily make a watch better and add little value.
Jump Hour Indicator: shows the hour in a dial cut-out window as a number and replaces the hour hand. The word jump is used as at the end of the 59th minute of the hour the numeral 'jumps' to the next hour rather than show any area between numbers.
Karat or K (Carat): Indicates purity of the metal identified as the number of 1/24th's of the pure metal in the alloy. 24K gold is pure gold as all 24 parts are gold. 18K gold has 18 parts gold and 6 parts of another metal. The indicator 0.750 also signifies 18K as 18/24 = 0.750 which is 750 parts per thousand or 75%.
Kif: A trade name for a shock absorbing system; in a similar vein to Incabloc above.
Kinetic: See also Battery-less QuartzA Seiko trade name for a line of quartz movement battery-less watches. Wrist movement charges a capacitor that provides power for the quartz movement. Fully charged, various models can store energy for between 3 to 14 days when not worn.
Lap Memory: A function of some quartz sport watches (usually digital watches), to record in the watch's memory times of race laps determined by the lap timer (see "lap timer"). These times can be recalled by pushing a button.
Lap Timer: A chronograph function that times various segments of a race such as laps.
LCD -Liquid Crystal Display: the electronic display of most modern digital watches. Uses less power than LED which means the time can be displayed constantly. A thin layer of liquid is held between 2 transparent plates.
LED - Light Emitting Diode: display of the first quartz digital watches. The LCD was preferred as it used vastly less power than the LED thus the time could be shown constantly as opposed to having to press a button for time display.
Lithium batteries: Deliver 3 volts and are longer lasting than Silver oxide batteries which only deliver 1.5 volts.
Lugs: Extensions or protrusions on the sides of the watch case where the bracelet or strap is attached. Part or parts of watch case to which band, bracelet or strap may be attached. Various types of lugs are rounded lugs, teardrop lugs and hidden lugs.
Magnified Window (Cyclops): A small window or lens in the crystal that is added to magnify the date 2 1/2 times.
Mainspring: a flat spring coiled in a barrel the forms the principal spring in a watch. A wound mainspring slowly and evenly unwinds to release energy that powers the watch.
Manual Winding: a manual mechanical watch in which the mainspring must be wound with the winding crown. Once wound the mainspring slowly unwinds releasing energy that powers the watch.
Mean Time: the calculated average length of all solar days in year.
Mechanical Movement: Watch movement based around a mainspring. A manual mechanical watch needs to be wound on a consistent basis, an automatic mechanical requires no winding as it has a rotor.
Military or 24 Hour Time: Time measured in 24-hour segments. To convert 12-hour time to 24-hour time, simply add 12 to any p.m. time. To convert 24-hour time to 12-hour time, subtract 12 from any time from 13 to 24. eg 6pm is 12+6=18 on a 24hour measurement.
Mineral Crystal: A watch crystal that is a form of glass. While more scratch resistant than acrylic, it will still scratch and is extremely difficult to polish.
Minute Repeater: Repeating watch that can sound when striking hours, quarters or minutes.
Month Aperture: Pierced window in the dial of a watch that displays the month.
Moon Phase: An indicator that tracks phases of the moon. The moon regularly rotates once around the earth every 29 days, 12 hours and 44 minutes.
Mother-of-Pearl: The milky and iridescent interior of the freshwater mollusc shell. Often used on watch dials.
Movement: The complete working mechanism of a watch made up of various components and a power source that work together to keep time. A mechanical movement uses a spinning balance wheel powered by a tightly wound spring. A quartz movement measures the vibrations in a piece of quartz and often is powered by a battery. The number of components can vary from 120 to over 600 parts.
Nivarox/Nivaflex: Trade names for self compensating metal alloys used in many Swiss watch mainsprings and hairsprings. These alloys are both strong and resistant to corrosion. They expand and contract to allow for the effects of temperature.
Omega-matic: See Battery-less Quartz
O-Ring: A plastic or rubber ring used for improving water resistance by sealing the backs of watches which screw on or press-in. O-rings are also used for water and dust protection around the winding stems and crowns.
Oyster Case:The Rolex name for a water-resistant case.
Pave: Means "paved with". A dial paved with precious stones is said to be pave set.
Pedometer: A mechanism that responds to the impact of each step of the wearer and records the number of strides.
Perpetual: A Self winding automatic watch.
Perpetual Calendar: A calendar mechanism that adjusts automatically to account for the different lengths the months (30 or 31 days) and automatically correct for leap years. Perpetual calendars may be pre-programmed until the year 2100.
Platinum: A rare, precious, strong and heavy metal and is quite expensive. Platinum is a white metal with a rich lustre, is tarnish resistant and hypoallergenic. Platinum watches are usually limited in edition due to rarity and cost of the metal.
Power Reserve:How long a watch is expected to run continuously when fully wound or powered with a new battery.
Power Reserve Indicator: Just as it says – an indicator the warns of a reduced power reserve so that the watch can be wound or have its battery replaced before the watch stops completely.
Pulsimeter: A marked scale feature of a chronograph watch used to measure the pulse rate.
Push-Piece: Simply a knob or Button that must first be pressed to activate a specific feature mechanism. Normally related to alarms and found on chronograph watches.
Quartz: A digital or analogue watch that draws its power from a battery powered quartz crystal that Oscillates at 32,768 times per second to maintain extremely accurate timing.
Quarter Repeater: A mechanism which repeatedly sounds on the hours and quarters. (i.e. each 15 mins)
Rattrapante: see Flyback. A term used to describe the split seconds chronograph (seeFlyback) which has two seconds hands sitting atop one another. On depression of a third chronograph button the flyback hand stops in order to measure say, a lap time. The flyback hand, literally 'flies-back' to the other second hand (which has continued its motion) when the button is pressed again.
Rattrapante Chronograph: A chronograph equipped with a flyback hand (rattrapante). This increased increases the potential uses of the watch significantly by making the measurement of split second times or timing simultaneous events of unequal duration possible.
Register: Another term used for a subdial. a dial within the area of the main dial of a watch. Most commonly seen on chronograph watches. Registers can be for minutes, hours, the day or date.Repeater: A device that chimes at set intervals such as minutes, quarters or hours. when a bthe wearer pushes a button. Some repeaters, called "quarter repeaters"
Retrograde: describes a watch dial pointer hand that returns to a zero point at the end of a set period. Example; a retrograde date pointer springs back to 1 after it has reached 31.
Rhodium Plated: A thin layer or rhodium a hard, brittle metal that is malleable only when heated to extreme temperatures applied as a protective coating as it does not oxidize.
Rolled Gold: Gold that is pressed onto another metal from sheet form.
Roman Numerals: Commonly used numerals for watch dials. Instead of IV for 4, the form IIII is used.
Rose (or pink) Gold: A gold alloy that contains copper to give a soft pinkish hue rather than yellow.
Rotating Bezel: Simply a bezel that can be rotated around the watch dial. The function of the rotation lies in different timekeeping functions assisted by markings on the bezel.
Rotor: The part that winds the mainspring of an automatic / self-winding mechanical watch.
Sapphire Crystal: A watch crystal made from synthetic sapphire which ranks on the Moh scale at 9 indicating it is highly scratch resistant but is still subject to shattering under high impact stress.
Sapphlex Crystal: A Seiko Watch crystal made by fusing a mineral and sapphire crystal together.
Screw-Down Locking Crown: A design feature found mainly only in watches that must be extremely water resistant. It allows the watch winding crown to screw tightly into the case of the watch.Second Time Zone Indicator: An additional dial used to set the time of another world time zone.
Self-Winding: A mechanically powered watch wound by the wearers arm motion that causes the rotor to turn and wind the mainspring, rather than by manual winding of the stem. Normal power reserve is about 36 hours and the watch will wind down if not worn for a day or two. Manual winding is then required to start the watch again.
Shock Resistance: This term relates to the ability of the movements of the mechanical watch components to withstand a shock. As defined by the U.S. government regulation, a watch's ability to withstand an impact equal to that of being dropped onto a wood floor from a height of three feet and it does not stop, or if its daily rate does not change by more than sixty seconds.
Signed Movement : A movement that has been signed by its maker and is more often than not different to a signature that may appear on the casing or dial.
Silver Oxide Batteries: not as long lasting as lithium batteries that deliver double the1.5 volts of silver oxide batteries.
Skeleton Watch: The mechanisms of the interior movement are visible. The dial has a separate chapter ring with the interior cut away, the back plate is also cut away and fitted with glass.
Slide Rule Bezel: A rotating bezel, marked with a logarithmic scale and assorted other scales. It is used in conjunction with mathematical fixed rules to perform general calculations or navigational computations.
Solar Powered: the batteries of quartz movement are recharged via solar panels on the watch dial. a power reserve so they can run even in the dark.
Split Second: A chronograph feature of two hands, one a regular hand and the other a flyback or sweep hand. The flyback hand can be stopped independently of the regular hand allowing laps or different finishing times to be timed.
Stainless Steel: A chromium metal alloy that is extremely durable, virtually immune to rust, discoloration, corrosion and can be highly polished. Frequently used on case backs as it does not contain nickel and is therefore hypoallergenic, making it perfect for the area that has high contact with the skin.
Sterling Silver: One of the precious metals. Sterling is silver that is 92.5 percent pure. As silver can tarnish a protective coating may be applied.
Stopwatch: A watch with a seconds hand that measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stop watch function and the timepiece are referred to as a "chronograph".
Strap: A cloth, rubber, leather or other non-metal material watchband.
Subdial / Subsidary Dials: See Register. A small auxiliary dial within/on the main watch dial.
Sweep Seconds: The seconds hand of a watch. Like the hour and minute hand it is mounted at the centre of the dial.
Swiss A.O.S.C. (Certificate of Origin): An identifying mark on a Swiss assembled watch watch. I.e. a watch assembled in Switzerland with components of Swiss origin, primarily used in Bedat watches.
Tachometer (Tachymeter): An instrument/scale that measures speed in units per hour. a graduated bezel dial from which speed can be read off in kilometres or miles per hour. Using the seconds hand an event is timed. When stopped the second hand points to the number of units per hour.
Tank Case: Once an exclusive Cartier term but now a common name for a rectangular case. The Cartier watch of rectangular shape with heavier bars to dial sides. So named as the design was inspired by WWI tank tracks.
Tantalum: A metal similar in color to gold and in texture to titanium.
Telemeter: A watch function that measures how long it takes for sound to travel the distance between the wearer and a given object using a stopwatch. A chronograph dial is then used to find the distance between object and wearer.
Timer: Measures intervals of time (duration, brief times), independently to the time of day.
Titanium: A silver-grey metal. Often referred to as a space age metal, since it is almost 50% lighter than steel and 30% stronger. Being resistance to salt water corrosion and hypoallergenic it is useful in metal for watches.
Tonneau Watch: a wide centred barrel-shaped watch case and two convex sides of flat tapered ends.
Totalizer: A mechanism that records and displays elapsed time.
Tourbillon: complex micro-engineering that functions to correct for errors that could occur in relation to the varying effects of gravity on different positions.
Tritium: A hydrogen isotope used in luminous compounds which glow in the dark.
Two Tone: A term that describes both silver and gold in the same place.
UTC: Universal Time Coordinated. A universal time based on the Greenwich Meridian used by the military and in aviation. Greenwich Mean Time (GMT) can be considered approximately equivalent to Universal Time Coordinated (UTC). GMT as such is now obsolete however, being replaced by UTC. Using this timezone/standard avoids errors and problems associated with different time zones and summer times operational in different countries.Water Resist / WR: Protection of varying levels to water damage indicated by their capability to withstand water pressure at certain depths. Ranging from WR30 Meters for an everyday watch to 100M for frequent swimming and 200M and over for diving and specialty watches. Water resistant watches is measured on the ability to withstand water pressure at a depth of 1m for 30 minutes and thereafter 90 seconds at 20 meters.
Waterproof: the Federal Trade Commission states no watches are 100% waterproof therefore watches cannot be marked as being any more than water resistant. Certain parts of a watch may be waterproofed to certain water depths.
Winder/Winding Crown/Winding Stem: See Crown - The button on the side of the watchcase used to wind the watch. Normally the crown is pulled away from the case to wind hence the term stem. Also used for setting or changing the time and date.
Winding: The motion of turning the crown, or the automatic action of a rotor, that tightens the mainspring to provide power for the watch.
World Time Dial: A dial normally around the outer edge of the watch face marked with indicators for the 24 world time zones.
Yacht Timer: A timer that counts down and sounds warning signals at one or more predetermined times as zero is approached to give warning of how much time is remaining. Named a yacht timer as it is used during the countdown to the start of a boat race so the best possible starting position can be achieved.
Zulu Time: An aviation and military term refering to GMT & UTC. Z represents the zero meridian that passes through Greenwick and Zulu is the phonetic used by aviation and military communication to confirm the letter Z.
