ACCELERATION SENSOR See distance calculator.
ACRYLIC Acrylic is a synthetic plastic made from vinyl compounds. It is commonly used for bands and can be used for cases.
ADJUSTABLE BAND An adjustable band usually refers to leather, silicone, rubber, nylon, canvas or any other pliable material that wraps around your wrist and fastens with a buckle. Because there are holes in the band, the buckle is designed to be adjustable. An adjustable band may also use Velcro instead of a buckle and band with holes.
AFTERGLOW Afterglow is a function of the electroluminescent (EL) backlight that keeps the dial illuminated for several seconds after depressing the backlight button.
ALARM An alarm is a warning notice given via vibration or sound on the minute or hour or for a specific event.
ALTIMETER An altimeter provides altitude information, including current altitude, average altitude for the day, and an alarm when a certain altitude is reached.
ALUMINUM Aluminum is a lightweight metal with a satiny finish that is both comfortable and attractive. It is most common in watch cases, but can also be found in watch bands.
ANALOG An analog watch uses hands to indicate the time.
ANALOG-DIGITAL An analog-digital watch indicates time with hands (analog) in addition to showing time in a digital format.
APERTURE Aperture is the small opening in the dial that displays certain information such as date, day, month or moon phase.
ATM ATM is an abbreviation for "atmospheres" and it is used to express a watch's water resistance. One ATM is equivalent to 10 meters of water resistance.
ATOMIC TIMEKEEPING Atomic time is measured through the vibration of atoms within a metal isotope that resembles mercury. The result is extremely accurate time measurement. Worldwide radio towers transmit this exact time, which can be received on atomic watches and clocks. An atomic timekeeping watch or clock will receive time calibration radio signals up to several times per day.
AUTOMATIC CALENDAR See perpetual calendar.
AUTOMATIC WATCH An automatic watch is a self-winding, mechanical watch that uses your arm movement to power the mainspring, which runs the watch. Automatic watches do not require a battery. If not worn every day, an automatic watch needs to be wound by hand or using a watch winder in order to keep precise time.
AUTOMATIC QUARTZ MOVEMENT See kinetic movement.
BACKLIGHT Sometimes called an electroluminescent (EL) backlight, this function lights up the dial at the push of a button.
BANGLE A bangle watch is usually hinged, has no clasp and looks like a bangle or cuff bracelet. These can be ornate and are common in fashion watches.
BAROMETER A barometer displays current air pressure and can indicate air pressure trends.
BATTERY POWER A battery is one of the most common power sources for watches. Battery-powered watches are available in both analog and digital form.
BATTERY POWER INDICATOR Many watches have a battery power indicator, or energy depletion forewarning function, which signals that watch power is low.
BEZEL The bezel of a watch is the ring that holds the protective crystal in place. Some watches have rotating bezels you can use for timing purposes or mathematical equations like average speed or distance.
BRACELET A bracelet typically refers to a metal band. A bracelet-type band may or may not be adjustable.
BUCKLE Similar to the clasp on a belt, a buckle holds an adjustable watch band in place using one of a series of holes.
BUTTERFLY CLASP See hidden deployment clasp.
CABOCHON Crowns are commonly decorated with a cabochon, a gemstone that is shaped and polished rather than faceted. It is typically cut in a half-spherical shape.
CALCULATOR Some watches include a calculator mode that allows you to add, subtract, multiply and divide.
CALENDAR The calendar is most commonly available with just the date or the date and month displayed.
CANVAS Canvas is a strong woven fabric used for bands.
CARBON FIBER Carbon fiber is a strong, lightweight, thin weave constructed of bonded carbon atoms. It is often used for watch dials, but can be used as an accent on bands and cases as well.
CASE The case is the housing that holds a watch's internal workings.
CERAMIC High-tech ceramic is incredibly durable, lightweight and scratch-resistant. It also has an attractive, satiny finish, making it perfect for dress watches. Ceramic can be used in both watch cases and bands.
CHRONOGRAPH A chronograph is a timepiece with two independent time systems. One indicates the time of day and the other measures brief intervals of time. Counters that register seconds, minutes and hours can be started and stopped, measuring exact durations. These can be found on both analog and digital watches.
COMPASS A compass indicates direction. Watch compasses can be magnetic or digital.
COMPLICATIONS Complications are any additional features or functions a watch offers beyond standard time and date.
COUNTDOWN TIMER A countdown timer counts backwards for a desired duration.
CROWN Known as the winding crown or winder, the crown is used to wind non-automatic watches, set the hands to the correct time and set the date on calendar-equipped models.
CUTAWAY DIAL See skeleton watch.
DATABANK The databank offers storage for information such as lap times, voice memos, text memos, distance traveled, calories burned and more.
DEPLOYMENT CLASP Usually found on metal bracelet-style watch bands, a deployment clasp opens out and unfolds, revealing a two-piece mechanism that makes the band large enough to fit over the wearer's hand.
DEPTH SENSOR A depth sensor is usually an electro-mechanical device. It measures how deep a diver is under water.
DIAL The dial is the face of the watch.
DIGITAL A digital watch displays time on a liquid-crystal display (LCD) or light emitting diode (LED) screen.
DISTANCE CALCULATOR A distance calculator uses your step count or GPS to calculate distance covered.
DUAL TIME A dual-time watch is able to display time in two different time zones simultaneously or as an additional function.
EXHIBITION BACK See skeleton watch.
EXPANSION BAND An expansion band is designed with expanding links that stretch to slide onto your wrist. It has no clasp.
FACE COVER The face cover is made of a hard crystal. Watch crystals come in many different materials, including scratch-resistant mineral crystal, non-reflective crystal (popular with sport watches) or sapphire crystal, which is one of the most expensive and durable. Some watchmakers use proprietary materials for their watch face covers.
FAUX LEATHER Imitation leather is made out of a variety of materials and used primarily in fashion watch bands.
FISHING/HUNTING TIMER A fishing or hunting timer will give you the best times to hunt based on your latitude and longitude and on the phases of the moon. This alarm is usually available in both audio and vibration modes.
FLAME FUSION CRYSTAL Flame fusion crystal is an impact-resistant synthetic crystal that combines mineral and sapphire.
FLIGHT COMPUTER Watches with flight computers are fitted with a rotary slide-rule bezel for rapid calculations and conversions of flight data, as required by pilots. The rotary slide rule consists of a bezel ruler and a dial ruler, providing a wide variety of computations and conversions.
FOB A fob is a chain or ribbon attached to pocket watch.
FOLD-OVER PUSHBUTTON DEPLOYMENT CLASP A fold-over pushbutton deployment clasp is usually found on metal bracelet-style watch bands. Similar to a standard deployment clasp, this clasp opens out and unfolds, revealing a two-piece mechanism that makes the band large enough to fit over the wearer's hand. This clasp has the added security of a latch which must be unfastened and buttons which must be pressed to release the latch.
GASKET Most water-resistant watches are equipped with gaskets to seal the caseback, crystal and crown from water. Gaskets need to be checked every couple of years to maintain water resistance.
GMT More recently known as Universal Time Code, Greenwich Mean Time (GMT) is kept by a highly accurate international clock at the Royal Observatory in Greenwich, England, and serves as the world's timekeeper of record.
GUILLOCHE Guilloche is a repetitive ornamental pattern consisting of two or more lines winding around a series of central points.
HEART MONITOR A heart monitor or pulse counter tracks your heart rate. Some heart monitor watches even provide data on heart-rate zones to let you know if you're below, at or above your desired heart rate.
HUNTING TIMER See fishing/hunting timer.
HYDRATION ALARM A hydration alarm reminds you when to drink water. This is especially handy for hikers and long-distance runners.
ION PLATING Ion plating is a method by which a coating of various metals or alloys is applied to a metal case or band. In the process, the molecules of metals or alloys used for plating enter the surface of the article being plated. This process allows for superior bonding and integrates the color of the alloy into the surface of the metal.
JEWELRY CLASP Usually found on metal bracelet-style watch bands, a jewelry clasp resembles closures commonly found on jewelry pieces. This simple clasp consists of a latch that snaps closed securely around a bar.
KINETIC MOVEMENT A kinetic watch converts your movement into a magnetic charge, then to electricity, which it can store for up to six months. As long as it is worn regularly, it never needs to be wound and never needs a battery.
LEATHER Commonly used for adjustable watch bands, leather is a durable material that offers a casual look and comfortable feel.
LIGHT POWERED See solar power.
LIQUID-CRYSTAL DISPLAY A liquid-crystal display uses a liquid held in a thin layer between two transparent plates. Many computer monitors and televisions also use LCD.
LOW-TEMPERATURE RESISTANCE Watches with low-temperature resistance will continue to operate even when they are exposed to extremely low temperatures.
LUGS Lugs are extensions from the top and bottom of the watch case where the band or bracelet is fastened.
LUMINOUS Some parts of a watch, like hour markers and hands, are coated with self-illuminating material that causes these parts to glow in the dark.
MAGNETIC RESISTANCE Mechanical watches have moving parts that are easily affected by magnets. Magnetic resistance protects the functionality of the watch from exposure to magnetic fields, ensuring the watch's precise timekeeping.
MAINSPRING The mainspring is the mechanism that runs any mechanical watch. It requires periodic winding either manually or automatically. Quartz (electrical) watches do not have a mainspring.
MANUAL MOVEMENT A mechanical watch that must be wound periodically in order to continue to keep precise time.
MANUAL POWER The wearer must manually wind the mainspring via the crown in a watch that requires manual power.
MECHANICAL WATCH A mechanical watch is any manual or automatic watch with a mainspring that requires periodic winding. This does not include quartz (electrical) watches.
MILITARY TIME 24-hour format, also referred to as military time, divides the day into 24 hour-long increments from midnight to midnight.
MINERAL CRYSTAL A synthetic mineral glass, mineral crystal is three times harder and more scratch-resistant than regular glass. It is also one of the most commonly used face covers.
MOON PHASE This feature depicts the phases of the moon.
NYLON BAND Nylon bands are tough, elastic synthetic fibers found in some sport watch bands.
OCCASIONAL ALARM See alarm.
ONE-WAY (UNIDIRECTIONAL) ROTATING BEZEL Found on most dive watches, a one-way rotating bezel moves only in a counterclockwise direction. This means divers can only underestimate their remaining air supply if they accidentally move the bezel while under water.
PACE COUNTER A pace counter is a signal to help maintain a desired pace.
PATENT LEATHER Patent leather is genuine or imitation leather coated with lacquer to achieve a hard, glossy surface.
PEDOMETER A pedometer counts the number of strides taken by the wearer by responding to the impact of the wearer's steps.
PERPETUAL CALENDAR A perpetual calendar automatically updates itself. It knows which months have 28, 30 and 31 days, and adjusts for leap years so you never need to reset the date.
POLYURETHANE Polyurethane is a plastic material commonly used for watch bands and sometimes for watch cases to prevent water or heat from passing through.
POWER RESERVE INDICATOR Many mechanical watches have a power reserve indicator, or energy depletion forewarning function, to signal the amount of remaining energy stored in the mainspring (how long until it needs to be wound again).
PUSHBUTTON DEPLOYMENT CLASP A pushbutton deployment clasp is usually found on metal bracelet-style watch bands. Similar to a standard deployment clasp, this clasp opens out and unfolds, revealing a two-piece mechanism that makes the band large enough to fit over the wearer's hand. This clasp has the added security of buttons which must be pressed to release it.
PULSE CALCULATOR See heart monitor.
QUARTZ MOVEMENT A quartz watch regulates the passage of time using a quartz crystal and an integrated circuit. Most quartz watches are battery-powered; however, automatic quartz watches contain capacitors that can be recharged by the wearer's daily movement.
REPEATER A repeater is a watch that chimes the hour, quarter hour and minutes.
RESIN Resin is a durable, synthetic type of thermosetting plastic that can be made into any number of shapes and colors. It is often used in fashion and sports watches.
RETROGRADE Instead of traveling 360 degrees before starting a new measurement, retrograde hands move on an arc (usually 90 degrees or 180 degrees) then immediately return to their starting point. These hands commonly display date, day and month.
ROTATING SLIDE RULE See flight computer.
ROTOR The rotor is the weighted element on a mechanical watch that winds the mainspring.
RUBBER Due to its soft and flexible nature, rubber is frequently used in watch band construction, but it also can be used in case construction.
SAPPHIRE-COATED MINERAL CRYSTAL Mineral crystal coated with sapphire crystal provides a durable, scratch-resistant face cover.
SAPPHIRE CRYSTAL Sapphire crystal is made from aluminum oxides to create a clear synthetic sapphire, which is ground and polished to a high brilliance. It is more scratch-resistant than mineral crystal.
SCREW-DOWN CASEBACK Used on many high-grade, water-resistant watches, a screw-down caseback provides a positive seal on the back of the watch case.
SCREW-DOWN CROWN Used on many high-grade, water-resistant watches, a screw-down crown provides a positive seal between the case and the crown.
SHOCK RESISTANCE Shock-resistant watches can be worn during vigorous activities without jarring the small parts inside the watch.
SILICONE Silicone is a soft, pliable, rubber-like material commonly used for bands because it is extremely comfortable to wear.
SKELETON WATCH A skeleton watch shows the inner workings of the watch through a cutaway dial or caseback.
SOLAR POWER A solar-powered watch converts any natural or artificial light source into energy. When fully charged, a solar-powered watch can last up to several months before having to be recharged.
SPLASH RESISTANCE Splash-resistant watches are resistant to minimal water exposure, like light rain. They are not suitable for swimming or submersion.
STAINLESS STEEL Stainless steel is highly resistant to rust and ordinary corrosion, making it an excellent metal for both cases and bands.
STATIONARY BEZEL A stationary bezel does not rotate.
STRETCH BAND Usually seen in fashion watches, a stretch band has no clasp and stretches to fit over the wearer's wrist.
SUBDIAL Subdials are smaller dials on the main dial. They are used for additional time keeping functions (e.g., as a chronograph, date display or 24-hour display).
SUN/MOON DISPLAY A sun/moon display shows the position of the sun and moon in the sky.
SUNRAY DIAL Usually metallic, a sunray dial has tiny ridges extending from the center of the dial. It is a decorative design that mimics the sun's rays.
SUNRISE/SUNSET DIAL A sunrise/sunset dial displays the time the sun rises and sets each day.
TACHYMETER A tachymeter is a device on the chronograph watch that measure the speed at which the wearer has traveled over a measured distance.
TELEMETER A telemeter determines the distance of an object from the observer. Like a tachymeter, it consists of a stopwatch or chronograph and a special scale, usually on the outermost edge of the watch face.
TIDE GRAPH A watch with a tide graph will calculate tide information based on longitude.
TITANIUM Titanium is scratch-resistant and lightweight, resulting in a tough watch that doesn't weigh you down.
THERMOMETER A thermometer measures the temperature of the surrounding environment.
TUNGSTEN Tungsten is an extremely durable and scratch-resistant metal that allows for a high gloss.
TWENTY-FOUR HOUR FORMAT (24-HOUR FORMAT) See military time.
UNIDIRECTIONAL BEZEL See one-way rotating bezel.
VIBRATION ALARM See alarm.
WATER RESISTANCE Often indicated by a number next to a "WR" on the watch face or caseback, water resistance measures your watch's ability to withstand being submerged in water without sustaining damage.
WATCH WINDER A watch winder is a device used to wind mechanical watches. It can be used to wind kinetic or automatic watches that have stopped running. Watch winders are recommended for people who do not wear their automatic watches every day or do not generate enough movement to recharge the internal capacitor.
WEATHER MODE Depending on the watch, weather mode can show barometric pressure, temperature, forecast, cloud conditions, sunrise/sunset times and more.
WORKOUT REVIEW Workout review gives a summary of measurable workout results.
WORLD TIME A world time watch gives you the time for specific cities or time zones around the world. The number of cities or time zones depends on the make of the watch.
WRAP BAND Usually found on fashion watches, a wrap band coils around the wrist more than once to give the illusion of layers or a complementary bracelet.