12-Hour Recorder (or Register):
A 12-hour recorder (or register) is a sub dial on a chronograph that can record time periods of up to 12 hours.
30-Minute Recorder (or Register):
A 30-minute recorder (or register) is a sub dial on a chronograph (see "chronograph") that can record time periods of up to 30 minutes.
Acrylic Crystal:
Sometimes referred to as Hesolite, an acrylic crystal is made up of plastic composite that is generally less expensive and less durable than a sapphire or a mineral crystal. Its flexible, malleable make up means it will not shatter on impact. It also produces fewer glares under bright lights and can be easily polished.
Alarm:
An alarm is a device that makes an alerting sound at a preset time. Alarm watches can be either Quartz or mechanical.
Altimeter:
An altimeter is a function that shows altitude by responding to changes in barometric pressure. Altimeters are commonly found in pilot watches or inside a pressurized airplane cabin.
Analog Watch:
An analog watch has a dial, hands, numbers, or other types of markers that present a total display of 12 hours.
Analog-Digital Display:
An analog-digital display watch shows the time by means of hands (analog display) as well as by numbers (digital display). The analog display has a traditional dial with hour, minute, and sometimes second hands. The digital display shows the time in Arabic numerals with a liquid crystal display. This feature is usually found on sport watches.
Annual Calendar:
A watch showing the day, date, month, and 24 hours, adjusting automatically for short and long months is called an annual calendar watch. The calendar needs setting only once a year between the end of February and the first of March.
Aperture:
Apertures (montres à guichet in French) are small openings carved into the watch that display certain indications such as the date or hour. Such apertures may only be visible when the watch dials are at certain positions.
Atmosphere (Atm):
Atmosphere (Atm) measures the normal pressure of the air at sea level; it is used in watch making to indicate water resistance.
Atomic Time Standard:
Provided by the U.S. National Institute of Standards and Technology, Time and Frequency Division in Boulder, Colorado, atomic time is measured through vibrations of atoms in a metal isotope that resembles mercury. The result is extremely accurate time that can be measured on instruments. Radio waves transmit this exact time throughout North America enabling some atomic watches to correct themselves to the exact time.
Automatic Movement / Automatic Winding (also called self-winding):
Mechanically powered automatic movement or automatic winding watches are wound by the motion of the wearer's arm rather than by turning the winding stem. In response to this motion, a rotor turns and winds the watch's mainspring so that it keeps accurate time. Most automatic watches have up to 36 hours of power reserve. If an automatic watch is not worn for a day or two, it will need to be wound by hand to restart again.
Battery End-Of-Life Indicator (EOL):
The battery end-of-life indicator function signals an impending battery failure in a Quartz watch by means of the second hand jumping in two- or four-second intervals. The watch has approximately two weeks before battery failure.
Battery-less Quartz:
These modern timepieces use hybrid technology so that they can run smoothly without manual winding. These watches use movement powered from a small, electrical generator. Energy is stored in a rechargeable battery or similar device in order to keep the watch running properly. Commonly known under proprietary names such as Kinetic (Seiko), Omega-matic (Omega), and Auto Quartz (Invicta), battery-less Quartz watches function like automatic watches and must be worn regularly to maintain their electrical power reserve.
Bezel:
Generically, the bezel refers to the upper part of the watch body. Specifically, it usually refers to a ring that goes around the outside of the crystal. On jewelry watches, for instance, the bezel may contain a ring of diamonds. On sports watches, the bezel may show calibrated markings and have the ability to rotate in one or two directions.
Bidirectional Rotating Bezel:
A bidirectional rotating bezel can be moved either clockwise or counterclockwise and is usually used for mathematical calculations or for keeping track of elapsed time.
Cabochon:
Decorative in its purpose, a cabochon indicates a smooth round or oval, convex-shaped polished gemstone set in the watch crown.
Case or Watchcase:
The case or watchcase refers to the metal housing that contains the internal parts of a watch. Most cases are made up of stainless steel but titanium, gold, silver, and platinum are also used.
Case Diameter:
On Amazon.com, the case diameter is an approximate watch measurement that includes the crown. (Some watch merchandisers do not include the crown in this measurement.
Chronograph:
A chronograph is a multifunction sport watch with a stopwatch function. Most have two or three sub dials or mini dials for measuring minutes and hours. When used in conjunction with specialized scales on the watch dial it can perform many different functions, such as determining speed or distance (see "tachometer" and "telemeter"). Some chronographs can time more than one event simultaneously (see "fly back hand" and "split seconds hand"). Chronograph Rattrapante: The addition of a fly back hand (rattrapante) on a watch significantly increases the potential uses for chronographs, making it possible to measure split-seconds of time or simultaneous events of unequal durations.
Chronometer:
This term refers to a precision watch that is tested in various temperatures and positions, thus meeting the accuracy standards set by C.O.S.C. in Switzerland. These watches are provided with a chronometer certificate detailing specific test results.
Countdown Timer:
The countdown timer is a function that lets the wearer monitor how many hours, minutes, or seconds have elapsed from a preset time. Some countdown timers sound a warning signal a few seconds before the time runs out. These are useful in sporting events such as races.
Crown:
The crown, often referred to as the winding crown or winder, is used for winding a manual watch, for setting the hands to the correct time, and for setting the date in calendar-equipped watches. On diving/sports models, the crown may screw down onto a threaded tube, which protrudes from the watch case to better ensure superior water resistance.
Crystal:
The covering of the watch dial is called the crystal. Three types of crystals commonly used in watches are: acrylic, mineral, and sapphire. Acrylic crystal is an inexpensive plastic that allows shallow scratches to be buffed out. Mineral crystal is composed of several elements that are heat-treated to create an unusual hardness that helps resist scratches. Sapphire is the most expensive and durable crystal, approximately three times harder than mineral crystals and 20 times harder than acrylic crystals. A non-reflective coating on some sport styles prevents glare, for instance.
Crystal Skeleton Caseback:
A crystal skeleton caseback is made of transparent material such as hardened mineral or sapphire crystal that reveals the intricate mechanical movements of the watch.
Cyclops (Magnified Window):
A Cyclops (or magnified window) is a small window or lens in the crystal that is added to magnify the date to two and a half times for enhanced readability.
Deployment Buckle (Foldover):
A deployment buckle, also known as a foldover, is a three-folding enclosure that secures the two ends of the bracelet allowing enough room for placing the watch on the wrist when fully deployed. When closed, the buckle covers the two-piece folding mechanism.
Depth Alarm:
Divers wear depth alarm watches that sound when the wearer exceeds a preset depth level. In most watches, the alarm stops sounding when the diver ascends above the preset level.
Depth Sensor/Depth Meter:
Divers wear depth sensor or depth meter watches to determine their depth level by measuring water pressure. Readings may be shown using analog hands and a scale on the dial or on a digital display.
Diver's Watch:
Divers' watches traditionally feature a graduated rotating bezel, a screw-down winding crown, and a caseback; such watches must be water resistant to at least 200 meters (660 feet).
Dual Time:
The term dual time refers to a watch that measures current local time as well as at least one other time zone. The additional time element may come from a twin dial, extra hand, sub dial, or other means.
Dual Time/Second Time Zone Bezel:
A dual time/second time zone contains a rotating bezel, which can be used to display a separate time zone distinct from that shown on the dial.
Elapsed Time:
Elapsed time refers to the actual amount of time it takes for an object to travel over a specified distance.
Elapsed Time Rotating Bezel:
A graduated rotating bezel (see "rotating bezel") is used to keep track of designated periods of time. The bezel can be turned so the wearer can align the zero with the watch's seconds or minutes hand. The wearer can then read the elapsed time off the bezel instead of having to calculate the elapsed time.
Fly back:
A fly back is an additional hand on a chronograph that moves with the second hand but can be stopped independently to measure a preset interval of time. It can then "fly back" to catch up with the second hand. This feature is useful for capturing lap times as well as finish times.
GMT Time zone:
Greenwich Mean Time (GMT), also known as Zulu Time, is set to the international clock in Greenwich, England. Through an additional hour hand, it reflects the world time on a 24-hour scale and is used by pilots across the globe.
Gold Plating:
The application of gold over the surface of an item is called gold plating.
Hand winding (Manual Mechanical):
A hand winding watch with a manual mechanical movement needs to be wound regularly by the wearer using the winding crown in order to keep accurate time. This motion winds the mainspring, which then releases its energy to power the watch.
Karat or K:
A karat is an indication of a metal’s purity, expressed as proportions of 1/24th of the pure metal used in the alloy. Metals such as gold are too soft in their pure state to use in jewelry, so they are typically made into an alloy for strength. 24K (equal to 24/24ths) is pure metal, and 18K is 18 parts pure metal mixed with 6 parts of other metals. That translates to 18/24=0.750, which is 75% pure or 750 parts per thousand.
Kinetic:
Referring to the Seiko line of Kinetic watches, this innovative technology has a Quartz movement that does not use a battery. Movement of the wearer’s wrist charges a very efficient capacitor that powers the Quartz movement. Once the capacitor is fully charged, men’s models will store energy for 7-14 days without being worn and ladies’ models will store energy for 3-7 days. The watch alerts the wearer to a low capacitor charge when the second hand starts to move in two-second intervals.
Lap Memory:
Some Quartz sport watches are built with a lap memory which enables the watch to store the times of laps in a race determined by the lap timer (see "lap timer"). The wearer can recall these times on a digital display by pushing a button.
Lap Timer:
A lap timer is a chronograph function that lets the wearer time segments of a race. At the end of a lap, the wearer stops the timer, which then returns to zero in order to begin timing the next lap.
LCD Display (Liquid Crystal Display):
An LCD display shows the time electronically by means of a liquid held in a thin layer between two transparent plates. It follows from the earlier LED or Light Emitting Diode display of the first Quartz digital watches. The LCD is preferred as it uses vastly less power enabling the time to be shown constantly instead of only when pressing a display button.
Magnified Window (Cyclops):
A magnified window, also known as a cyclops, is a small window or lens in the crystal that magnifies the date two and a half times.
Manual Winding:
Manual winding refers to a watch with a manual mechanical movement, which needs to be wound by the winding crown. This motion winds the mainspring up which then releases its energy to power the watch.
Mechanical Movement:
A watch’s mechanical movement is based on a mainspring, which, slowly unwinds in a steady motion to provide accurate timekeeping. As opposed to a manual mechanical watch, which needs to be wound on a consistent basis, an automatic mechanical watch requires no winding because its rotor winds the mainspring when the wearer moves their wrist (see the section on automatic watch maintenance for more details).
Military or 24 Hour Time:
When time is measured in 24-hour segments it is called military time. 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 13 to 24.
Mineral Crystal:
Mineral crystal is made from what is essentially a form of glass. More scratch resistant than acrylic, a mineral crystal will scratch and is extremely difficult to polish.
Moon Phase:
The moon phase is an indicator that keeps track of the phases of the moon. A regular rotation of the moon is once around the earth every 29 days, 12 hours, and 44 minutes. Once set, the moon phase indicator accurately displays the phase of the moon.
Mother-of-Pearl:
Mother-of-pearl refers to the iridescent milky interior shell of the freshwater mollusk that is sliced thin and used on watch dials. While most have a milky white luster, mother-of-pearl also comes in other colors such as silvery gray, gray blue, pink, and salmon.
Movement:
Movement refers to the means by which a watch keeps time and often includes the power source. For example, a watch with mechanical movement uses a spinning balance wheel powered by a tightly wound spring. A watch with Quartz movement measures the vibrations in a piece of Quartz and often is powered by a battery.
Pedometer:
Responding to the impact of the wearer's steps, a pedometer counts the number of strides a wearer takes.
Perpetual Calendar:
A perpetual calendar adjusts automatically to account for different lengths of months (30 or 31 days) and leap years. Perpetual calendars, which can be powered by Quartz or mechanical movements, are programmed to be accurate until the year 2100.
Power Reserve Indicator:
A power reserve indicator is a feature that shows when the watch will need a new battery or winding. A battery reserve indicator on a Quartz watch informs the wearer when the battery is low. Often this is indicated by the second’s hand moving at two- or three-second intervals. Seiko's Kinetic watches are Quartz watches that do not have a battery (see Kinetic). When a Seiko Kinetic needs to be wound, the seconds hand will also move in two-second intervals.
Power Reserve:
A power reserve measures the amount of time a watch will run after being fully powered or wound, with no additional power input. Normally, a mechanical watch that is fully wound or a Quartz watch with a new battery has a full power reserve. Many modern mechanical watches have a power reserve of 40 hours. Power reserve also applies to battery-less Quartz watches, which may have power reserves from 40 hours to 6 months. On battery-operated Quartz watches, the term power reserve is sometimes used to refer to the expected battery life--typically 12 to 32 months.
Pulsimeter:
A pulsimeter is the scale on a chronograph watch for measuring pulse rate.
Push-Piece:
The term push-piece refers to a button that is pressed to work a mechanism. Push-pieces are usually found on chronographs, striking watches, and alarms.
Quartz:
A Quartz is a caliber that uses the vibrations of a tiny crystal to maintain timing accuracy. The power comes from a battery that must be replaced about every 2-3 years. In recent years, new Quartz technology enables the watch to recharge itself without battery replacement. This power is generated via movement similar to an automatic mechanical watch, or powered by light through a solar cell (Kinetic & solar-tech).
Ratchet Bezel Ring:
A ratchet bezel ring can either turn one way (counter clockwise) or both ways and generally clicks into place.
Rattrapante Chronograph:
The addition of a fly back hand (rattrapante) significantly increases the potential uses for chronographs. It makes possible the measurement of split-second times or timing simultaneous events of unequal duration.
Register:
The register is another name for a sub dial that is usually found within the watch’s main dial. An example is a chronograph where there are registers for the chronograph minutes and hours. Some watches have registers with pointers showing the day and date.
Repeater:
A repeater is a device that chimes the time when the wearer pushes a button. Some repeaters, called "quarter repeaters" sound the hours and the quarter hours by means of two different pitched tones. Others called "five minute repeaters" sound the hours, quarters, and five minute periods while "minute repeaters" sound the hours, quarters, and minutes.
Retrograde:
Retrograde is used to describe a pointer-hand on a watch dial (often called a sub dial), which returns to zero at the end of a set period. For example, a watch may have retrograde date where the hand moves up a scale, pointing to the current date - when it reaches 31 it will spring back to 1.
Rhodium Plated:
Rhodium plated is the protective coating of metal with a thin layer of rhodium. It is a hard, brittle metal that does not oxidize and is malleable only when red hot.
Rotating Bezel:
A rotating bezel (the ring surrounding the watch dial) that can be turned in order to perform different timekeeping and mathematical functions.
Rotor:
A rotor is the part of an automatic (or self-winding) mechanical watch that uses movement to wind the mainspring. It is a flat piece of metal, usually shaped like a semicircle, which swivels on a pivot with the motion of the wearer's arm.
Sapphire Crystal:
Synthetically formed, the sapphire crystal of a watch is extremely scratch resistant (nine on the Moh scale) and is the material of choice for many watch collectors. The downsides are that the sapphire can chip at the edges if it protrudes and it can shatter.
Sapphlex Crystal (Seiko Watches):
Sapphlex crystal (found on Seiko watches) is a highly scratch resistant crystal created by the fusion of sapphire and mineral glass crystal.
Screw-Down Locking Crown:
A screw-down locking crown aids water resistance by sealing the crown to the case of the watch. A seal is achieved when the case locks with the crown's internal threads and gaskets fastening the crown into its place.
Second Time Zone Indicator:
The second time zone indicator is an additional dial that can be set to another time zone. It lets the wearer keep track of local time and the time in another country simultaneously.
Self-Winding:
Self-winding refers to a mechanically powered watch that is wound by the motion of the wearer's arm rather than by turning the winding stem (manual mechanical). In response to this motion, a rotor turns and winds the watch's mainspring. Most automatic watches have up to 36 hours of power reserve. If an automatic watch is not worn for a day or two, it will need to be wound by hand to get started again.
Shock Resistance:
As defined by U.S. government regulation, shock resistance is a watch's ability to withstand an impact equal to that of being dropped onto a wooden floor from a height of three feet.
Slide Rule Bezel:
A slide rule bezel is a rotating bezel or ring around the outside edge of the watchcase that displays a logarithmic or other scale. It is used to perform general mathematical calculations or navigational computations.
Solar Powered:
Solar powered refers to a type of Quartz movement where the batteries are recharged via solar panels on the watch dial. They have a power reserve so they can run in the dark.
Solar Tech:
Solar tech is a solar powered Quartz watch. This technology provides the accuracy of Quartz, without the inconvenience and cost of regular battery changes.
Split Second:
A split second is a feature on a chronograph that is two hands: one is a fly back and the other is a regular hand. In order to time laps or different finishing times, the wearer can stop the fly back hand independently while the regular hand keeps moving.
Stainless Steel:
Stainless steel is an extremely durable metal alloy (chromium is a main ingredient) that is virtually immune to rust, discoloration, and corrosion. It can be highly polished, thus resembling a precious metal. Stainless steel is often used on the backs of watchcases that are made of other metals. A metal of choice, stainless steel is used to make high quality watchcases and bracelets. It is also hypoallergenic because it doesn't contain nickel.
Sterling Silver:
Sterling silver, a precious metal, refers to silver that is 92.5 percent pure. The silver fineness should be stamped on the metal, sometimes accompanied by the initials of a designer or the country of origin as a hallmark. A protective coating may be added to prevent tarnishing.
Stopwatch:
A stopwatch with a second hand measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stopwatch function and the timepiece are referred to as a "chronograph."
Sub dial:
A sub dial is a small dial used for several purposes, such as keeping track of elapsed minutes or hours on a chronograph, or to indicate the date.
Swiss A.O.S.C. (Certificate of Origin):
The Swiss A.O.S.C. is a mark identifying a watch that is assembled in Switzerland with components of Swiss origin. It is primarily used in Bedat watches.
Tachometer (Tachymeter):
A tachometer is an instrument for measuring speed or units. In watch making, a timer or chronograph with a graduated dial shows speed in kilometers per hour or some other unit (see timer).
Tank Watch:
A tank watch is a rectangular watch with heavier bars on either side of the dial. It was inspired by the tank tracks of World War I and was first created by Louis Cartier.
Tantalum:
Tantalum is a metal with a texture similar to titanium, but a color similar to gold. This metal is used by Omega for the gold-like trim on certain titanium watches. Many of these watches are also available in titanium with real gold trim.
Telemeter:
A telemeter is a watch function that finds the distance of an object from the wearer by measuring how long it takes sound to travel that distance. Like a tachometer, a telemeter consists of a stopwatch function and a special indication on the dial of a chronograph.
Timer:
A timer is an instrument used for registering intervals of time without displaying the time of day.
Titanium:
Titanium is a "space age" metal, often having a silver-gray appearance. Because it is 30 percent stronger and nearly 50 percent lighter than steel, it has been increasingly used in watch making, especially sport watch styles. Its resistance to salt water corrosion makes it particularly useful in divers’ watches. Since it can be scratched easily, some manufacturers use a patented, scratch-resistant coating. Titanium is also hypoallergenic.
Tonneau Watch:
A tonneau watch has a barrel-shaped watchcase and two convex sides.
Totalizer:
A totalizer is a mechanism that keeps track of elapsed time and displays it usually on the watch’s sub dial. It is sometimes called a "recorder" or "register." The term "totalizer" can be used more generally to refer to any counter on a watch.
Unidirectional Rotating Bezel:
The unidirectional rotating bezel, or an elapsed time rotating bezel, moves only in a counterclockwise direction and is often found on divers’ watches. It is designed to prevent divers from overestimating their remaining air supply. Because the bezel only moves in one direction, the diver can err only on the side of safety when timing the dive. Many such bezels are ratcheted, so that they lock into place for greater safety.
Water Resistance:
Water resistance describes the level of protection a watch has from water damage. See the "water resistance" section for a description of the different levels.
Waterproof:
Waterproof means the ability to completely exclude the possibility of water entering into any working portion of a watch. According to the Federal Trade Commission, no watch is fully 100 percent waterproof and no manufacturer that sells watches in the U.S. may label any of their watches as "waterproof." The FTC stipulates that watches be referred to as "water resistant."
Winding Stem:
The winding stem button resides on the right side of the watchcase and is used to wind the mainspring; it is also called a "crown."
Winding:
Winding refers to the tightening of the watch’s mainspring. This can be done by hand (by the crown) or automatically (by a rotor, which swings due to movements from the wearer's arm).
World Time Dial:
A world time dial, usually found on the outer edge of the watch face, tells the time in up to 24 time zones around the world. The time zones are represented by the names of cities printed on the bezel or dial. The hour hand points to a city along a set scale enabling the wearer to determine the time zone.. Watches with this feature are called "world timers."
Yacht Timer:
A timer that sounds warning signals during the countdown.
There are no hard rules about whether or not her wedding band should be the same metal as her engagement ring. Many women like the symmetry of two identically matching rings, others prefer the look of two distinctive bands of colour. Of course, you could even choose a platinum band to go with a white gold engagement ring—it's all personal preference.
Getting the right fit involves more than just careful sizing, you should also consider the general design of the ring. At Blue Nile, you have your choice of traditional or comfort-fit wedding bands. The traditional band has a flat interior surface and simple domed exterior. The comfort-fit band has slightly rounded inside edges to enable more comfortable long-term wear
At Blue Nile, men's wedding bands are available in 3, 4, 5, and 6mm widths. When selecting your width, consider the shape of your hand. Is your hand long and narrow or short and broad? Generally, your ring should match the shape of your hand. Narrow bands work best on narrow hands while broad bands are better for broad hands, but the bottom line is always personal preference. 
