ACRYLIC CRYSTAL: Sometimes referred to as Hesolite or Hesalite, an acrylic crystal is basically plastic. Polymethylacrylate is often used. Benefits of an acrylic crystal are that is flexes rather than shatters on impact, it doesn't produce too much glare under bright light and it can be polished easily.
ALARM: Alarm functions may be fitted (most commonly) to battery powered quartz watches; the alarm with beep at the pre-set time. There are mechanical alarm watches featuring a hammer, which produces the alarm tone at the pre-set time. Most noteworthy examples are perhaps the Jaeger Le Coultre Memovox.
ALTIMETER: this determines altitude based on changes in barometric pressure. In a pressurized airplane cabin, the altimeter registers as if on land. A rotating bezel is used to determine altitude.
ANALOGUE: watch with a dial, hands, and numbers or markers that display a twelve -hour time period.
ANALOGUE/DIGITAL: has a dual display digital and a conventional analogue watch.
ANCHOR ESCAPEMENT: the regulator that controls the speed of a mechanical movement.
A/m (ANTI-MAGNETIC): unaffected by magnetism. If the parts most affected by a magnetic field (balance, balance spring and escapement) are made of non-magnetic materials the watch is called anti-magnetic. Bomb squad experts require this type of watch. As used in the Bell & Ross Type Deminuer.
APERTURE: an opening in the dial that displays certain information such as date, day, month, or moon phase or even the movement/
APPLIQUE: numerals, images or symbols cut out and stuck to dial.
ATM: The measurement of pressure called an atmosphere. An atmospheric measure is the amount of air pressure at sea level that a watch can withstand. (1ATM= 1BAR= 10m= 33.3ft)
AUTOMATIC MOVEMENT: self-winding watch whose movement is mechanical. A fly wheel (the rotor) turns by the motion of your arm and winds the mainspring. The stored energy in a spring is turned into mechanical energy that creates the watch movement. These watches can be shaken or in most cases manually wound if the power reserve is depleted.
AUTO REPEAT TIMER: function that counts down time and then resets itself as soon as a preset time has elapsed. It repeats the countdown continuously until a button is pressed to stop the function.
BALANCE: mechanical watches are regulated with the balance and balance spring. The mainspring provides energy. The hairspring, coupled to the balance, makes it swing to and fro, dividing into equal parts. Each to and fro of the balance is called oscillation. One oscillation equals 2 vibrations. (Heart of the mechanical watch).
BALANCE SPRING: A very fine spring in a mechanical watch that causes the recoil of the balance wheel. The length and adjustment of its length regulates the timekeeping. This is also known as the hairspring.
BALANCE WHEEL: regulating organ of the watch, vibrating on a spiral hairspring. Lengthening and shortening of the balance spring makes the balance wheel go faster or slower to advance or retard the watch.
BAR: narrow metal rod fixed between the horns that attaches the bracelet or strap to the watch. Also called a lug or spring bar.
BARREL: cylindrical box containing the mainspring of a watch. The toothed rim of the barrel drives the train.
BARREL SPRING: this spring's tension controls the amount of energy transmitted to the measurement. Hooked to the barrel and arbor, when it is tensed it releases controlled energy.
BEAT: the number of times per second (Beats Per Second) or per hour (BPH) that a balance wheel goes through a full arc of motion or the vibrations per hour (VpH) (half oscillation, or "tick") of a movement.
BEZEL: the circle around the top of the crystal. Mostly used to hold the glass or crystal in place. A rotating ratchet bezel moves in some watches as part of a complication. Rotating bezels either rotate clockwise, counter clockwise, or both to assist in calculations.
BI-DIRECTIONAL BEZEL: a bezel that both clockwise and counter clockwise.
BRACELET: the metal links for securing the watch to the wrist watchband.
BRIDGE: the balance cock is attached to the bottom plate with pins. Fixed to the main plate to form the frame of a watch.
BUTTONS: push piece controls, usually at 2'oclock and/or 4'oclock on the dial to control the functions such as the chronograph or the fly back.
CALENDAR: a simple calendar is a complication that shows the date of the month. A day/date shows the date of the month and the day of the week. A complete calendar shows the day, date, and the month or moon phase.
CALIBRE: the size and configuration of a watch movement. The diameter of the movement measured in "Parisian lines," where 1=2.256mm.
CAMBERED: curved or arched dial or bezel.
CASE: The main body (Usually stainless steel) containing the dial and movement consisting of the case band, case back, and bezel.
CASEBACK: bottom of the watch that lies against your skin.
CERAMIC: used as a shield for spacecraft re-entering the earth's atmosphere, high tech ceramic is polished with diamond dust to create a highly polished finish. Most popular found in black and white.
CHRONOGRAPH: stopwatch function that uses sub dials to keep track of second, minutes, and hours.
CHRONOMETER: A chronometer is a high-precision watch capable of displaying the seconds and housing a movement that has been tested over several days, in different positions and at different temperatures, by an official neutral body (COSC). Each chronometer is unique, identified by a number engraved on its movement and a certification number given by the COSC. Each movement is individually tested for several consecutive days, in 5 positions and at 3 temperatures. Each movement is individually measured. Any watch with the denomination "chronometer" is provided with a certified movement.
COMPLICATION: an additional "function" added to a watch, such as a, stop watch, countdown timer, minute repeater, altimeter, asthometer, pulsometer, calendar, moon phase indicator, split second chronograph, power reserve indicator, alarm, etc.
C.O.S.C.: Controle Officiel Suisse des Chronometres (Official Swiss Chronometer Testing Institute) they test watches for several consecutive days, in 5 positions and at 3 temperatures. They either pass or fail the watch movement. If the watch passes it is certified as a "chronometer".
COUNTDOWN TIMER: A function which measures the remaining time in preset period of time.
CROWN: The grooved button on the outside of the case, used for setting the hands on a watch, and the day and date, where applicable. It is also used for winding the mainspring of a mechanical watch. The crown is also known as a winder or winding stem, the interface used to wind a mechanical watch and to set the time and/or calendar of a watch.
CYCLOPS: A lens on the glass/crystal to magnify the date.
DECORATED MOVEMENT: Some watch movements come highly decorated, for example with Geneva Stripes and blued screws. Whilst decoration may not improve function, it often indicates a degree of hand assembly/finishing and an attention to detail in the construction of a watch. Some watches show off the decorated movement through the use of a display back.
DEPLOYMENT CLASP: used to secure the bracelet or strap of a wristwatch, to the wrist. There are three basic types of clasps; fold-over clasp, jewellery clasp and butterfly-clasp (aka deploy ant/deployment buckle, hidden deployment/deployment buckle, hidden double-locking clasp).
DEPLOYMENT BUCKLE: This refers to two curved strips of hinged metal on a watch with a strap that fastens the strap tightly to the wrist. It tends to be a feature of quality watches and inhibits a watch falling from the wrist should it come undone.
DEPTH ALARM: An alarm set to sound when the wearer exceeds pre-set depth. The alarm stops when the diver ascends above pre-set depth.
DIAL: face of the watch that generally displays hours, minutes, and date etc.
DIGITAL: watch that uses an LCD or LED to display a continuous reading.
DISPLAY BACK: is a case back that is transparent (normally glass/sapphire crystal) so that movement may be viewed. (Also called: clear, see-through, skeleton, exhibition).
DIVERS WATCH: designed especially for divers whose lives depend on the reliability of their watch in the water.
DLC: (Diamond Like Carbon) a coating that produces a grey/black finish that is highly scratch resistant and corrosion resistant. This type of coating is like PVD, but even harder.
DUAL TIME ZONE: tells the local time as well as time in another time zone. (Sometimes referred to as a GMT watch).
EBAUCHE:(raw movement) unassembled movement, without escapement, balance, hairspring, or mainspring.
END OF LIFE: the end of power in a "mechanical" or "quartz" watch is indicated by the seconds hand, which jumps every 2, 3, or 4 seconds.
ESCAPEMENT: Is a mechanism made up of the escapement wheel, lever, and discharging roller, this acts to control the wheel movement and to provide pulses to pallets and thus the balance. It converts the energy of the mainspring into equal units of time. The escapement controls the amount of power released from the mainspring. The regularity is controlled by the balance and it's spring. The escapement controls the rotation of the wheels and thus the motion of the hands. It is fitted at the end of the gear train and is designed to interrupt the movement of the wheels at regular intervals.
EXHIBITION BACK: same as a "skeleton" or "display" back.
FLANGE: ring that the crystal sits on and separates it from the dial.
FLYBACK: function that allows a chronograph to be reset to zero without having to stop the chronograph first.
FREQUENCY: number of vibrations a second or oscillations per second, in hertz (Hz) of a quartz watch. The number of vibrations per hour (VpH) of a mechanical watch.
FULL ROTOR: automatic watches with rotors that travel 360 degrees in both directions.
FUNCTION: the same as a complication on a mechanical watch, but technically called a function on a quartz watch.
GEAR TRAIN: made up of the going barrel, which drive the centre wheel. The centre wheel drives the third wheel then the 3rd wheel drives the second wheel. The second wheel drives the escapement wheel. It is the system of gears that transmits power from the mainspring to the escapement.
GENEVA SEAL: The quality seal the displays the City of Geneva coat of arms. Watches must meet a least eleven strict criteria to be awarded the Geneva seal.
GMT: Greenwich Mean Time (GMT), a watch that has the capability of displaying two different time zones.
GRAND COMPLICATION: A Grand Complication is a combination of complications but it must have a perpetual calendar with or without moon phase indication), a split-second fly back chronograph and a minute repeater. Manufactures quite often include many other complications as well.
GUILLOCHE: decoration found on the dials of high-end watches.
HAIRSPRING: the (or balance spring) is attached to the balance and cock, and made of metal alloys. Its length determines the amount that the balance regularly oscillates: the shorter the spring the faster the watch runs. It returns the balance wheel back to a neutral position.
HALLMARK: a mark stamped into the case of the watch to provide information about the degree of purity of the metal used, the country of origin, the country of origin, the year of manufacture, the identity of the case's maker, trademarks, reference numbers, and/or serial numbers.
HAND: watches generally have three hands for seconds, minutes, and hours. They come in many different shapes: Pear, Breguet, Baton, Arrow, Skeleton, Luminous, Alpha, Dauphine and more.
HAND-WOUND WATCH: a watch that receives energy by hand winding the crown sometimes called a mechanical movement.
HELIUM ESCAPE VALVE: a helium escape valve is required for divers who spend a long time in hyperbaric chambers and breath helium enriched gas. Helium molecules are much lighter than air and can therefore penetrate most watches. When a pressurized enclosure, such as a diving bell, surfaces and is depressurized the helium rushes out of the watch so quickly that the crystal on the watch pops out. To avoid this the helium escape valve releases this helium from the watch while resurfacing. The helium escape valve allows helium to escape without water entering the watch.
HOROLOGY: science of time measurement, including the art of designing and constructing timepieces.
INDEX: instead of a number, a marking indicating the hour and/or minutes.
INTERNAL BEZEL: a bezel inside the watchcase usually with a separate or additional crown.
JEWELS: In the mechanical watch and some quartz watches, jewels (usually made from synthetic ruby) are used as bearings for those parts of the movement subject to constant motion. They are not valuable at all in the monetary sense but they are valuable in aiding the precise running of a watch over a long period and reducing wear. It is a fallacy that the more jewels the better the watch. A basic hand wound mechanical usually comprises 17 jewels, which in the main is the optimum count. Automatics may require more for the winding mechanism itself.
JUMP HOUR: a display in which the hour, shown through an aperture, instantly changes every 60 minutes.
LAP TIMER: a chronograph function that times segments of a race. At the end of a lap a push button stops the time and then returns to zero to time the next lap.
LUG: (same as horn) part of case where bracelet or strap is attached.
LUMINOUS PAINT: self-illuminating paint that is put on the hands and markers to read the time in low light situations. Super Luminova is the most popular type of luminous paint.
M: indicating the depth of water resistance (200m) shown on the back of a watch case -see metre.
MAIN PLATE: the base plate on which all other parts of a watch movement are mounted.
MAIN SPRING: the driving flat-coiled spring of a watch contained in the barrel, supplies power.
MANUAL-WINDING: a hand wound mechanical watch.
MANUFACTURE: a factory that makes its own components and assemblies at least one complete movement (calibre), in-house.
MARINE CHRONOMETER: a highly accurate timepiece enclosed in a box that is used for determining the longitude on board a ship. A marine chronometer is mounted on gimbals so that they remain in a horizontal position to maintain their precision.
MECHANICAL MOVEMENT: Is a movement with a balance wheel. Wound by hand or rotor. Dates back to the 14th century about 130 parts, or over 500 for the most complicated watches.
METRE: a measurement used to measure water resistance. (10m= 33.3ft= 1ATM= 1BAR).
MINUTE REPEATER: A function on a watch that can strike the time in hours, quarters, or seconds by means of a push piece. An extremely complicated function, cost is very high.
MINERAL CRYSTAL: Watch crystal made from what is essentially a form of glass. More scratch resistant than acrylic, a mineral crystal will however scratch and is extremely difficult, if not impossible to polish.
MOON PHASE: Displays: new moon, first quarter moon, full moon, and last quarter moon by means of a disk that rotates beneath a small aperture. The 29 and 1/2 day cycle of the moon.
MOVEMENT: The "motor" of a watch or the machinery that turn the hands, change the date, start/stop the chronograph. There are two classifications of movement, either mechanical or quartz electronic.
NON SCREW LOCKED CROWN: Easier to set than a screw locked crown, but it is less water resistant.
PALLADIUM: An Assayed and rare, lustrous metal that is whiter than platinum and slightly harder. It is part of the platinum group of metals. Palladium is tarnish resistant, electrically stable and resistant to chemical erosion as well as intense heat. It has been recently classed as a precious metal by all the Uk assay offices.
PERPETUAL CALENDAR: extremely elaborate complication that keeps track of the day, month, date, and sometimes even the moon phase, zodiac signs, decade, century, and which adjusts for the length of the month and for leap years. (Accurate until 2100)
PINION: A toothed wheel usually made of steel with a small number of teeth.
PLATINUM: one of the rarest precious metals as well as one of the strongest and heaviest.
POINTER CALENDAR: hands point to the date as opposed to appearing in an aperture.
POLISHED: brilliant meal surface obtained on the watchcase with a fine abrasive.
POWER RESERVE INDICATOR: In its purest sense, used to refer to how long a watch will run once fully wound. Thus a watch with a power reserve of 48 hours should run for that period. Often used to describe a watch, which has a power reserve indicator on the dial (usually a small pointer hand and a relevant scale).
PVD: (Physical Vapour Deposition) A method of coating watch cases by integrating titanium particles and then depositing gold for colour. (Usually comes in black finish).
QUARTZ: a natural or synthetic silicon dioxide crystal used in quartz analogue or solid state digital watches when activated by a battery or solar power, the thin silver of the crystal very predictably vibrates at an extremely high frequency (32,768 times per second) step motor, electric circuit block.
QUICK SET DATE: mechanism to set the date directly to avoid having to turn the hands over 24 hours.
RATTRAPANTE: used to describe the split seconds chronograph (see Fly back), which has two seconds hands sitting atop one another. On depression of a third chronograph button (most have two), the fly back hand will stop in order to measure say, a lap time; repressing this button with cause the fly back hand to fly back (!) to the other seconds hand which has remained in motion. Addition of a second hand to measure split times. (Also called split-second chronograph.)
REGULATOR: device inside a watch that speeds it up or slows it down to allow the more precise setting of the watch.
REPEATER: strikes the hour, half hour, minutes, seconds, or some combination of the two.
RETROGRADE: an hour, minute, seconds or calendar hand, which moves across a scale and, at the end of its cycle, returns immediately to zero to begin again.
ROTOR: part of an automatic watch that winds the mainspring. A flat piece of metal swivels on a pivot with the motion of the wrist. Its rotation continually winds the mainspring of the watch. It turns freely in both directions and uses the force of gravity to win the mainspring.
RUBIES: ruby is a very hard stone now usually synthetic, which prevents the wear of gear train parts. Also called jewels.
SAPPHIRE CRYSTAL: synthetic corundum crystal with a hardness second only to a diamond. Transparent sapphire is used for a scratchproof watch glass. Made of crystallizing aluminium oxide at very high temperatures. Chemically the same as natural sapphire, but colourless. It is hard and brittle so it shatters easier than plexiglass or mineral glass. 9 on a mohs scale, a diamond is 10.
SCREW-DOWN CROWN: seals the crown against the case to prevent water penetration.
SEAL: A gaskets that seals the joints between parts of the case and keeps out the water.
SELF-WNDING: See automatic watch.
SHOCK ABSORBERS: spring devices in balance wheel bearings that divert shocks away from the fragile pivot to the sturdier parts of the balance staff. The springs allow the balance wheel to return to its original position after shocks.
SHOT BLASTING: a satin finish obtained by using tiny glass pellets, one or two microns in diameter.
SKELETON MOVEMENT/DIAL: movement on a watch where the plates have been removed or trimmed so that you can see the gears and other parts.
SKELETON WATCH: visible movement through crystal on the front and back.
SLIDE RULE BEZEL: a rotating bezel that is printed with a logarithmic scale and assorted other scales and is used in conjunction with fixed rules of mathematics to perform general mathematical calculations or navigational computations.
SOLAR POWERED: batteries are recharged via solar panels on the watch face. (Citizen ECO-Drive).
SPLIT-SECOND CHRONOGRAPH: a split seconds chronograph or rattrap ante (catch up in French) or doppelchrono (double chrono is German) has two seconds hands, the first push starts both hands together, the second push stops one hand while the other continues, and another push allows the stopped hand to catch up with the moving seconds.
SPRING BAR: a spring loaded metal bar mounted between the case lugs used to attach the strap or bracelet.
STAINLESS STEEL: a Very durable metal alloy consisting of steel, nickel, and composed mainly of chromium. It is virtually rustproof. It is also antimagnetic and used in most watch case manufacture.
STEM: the Axel that connects to the movement's winding mechanism, the crown is normally fitted on the opposite end.
STOP SECOND: (same as hacking) crown, which can be pulled out to set the seconds on a watch accurately.
STOPWATCH: a watch with a seconds hand that 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 DIALS: extra dials or registers.
SUPERLUMINOVA: usually charged by UV light, photo-luminescent non-radioactive material with a long period of phosphorescence. Visible in the dark.
SWEEP SECOND HAND: Second hand that moves smoothly without starts and stops. (Usually on a Swiss watch).
SWISS MADE: legally protected indication of Swiss origin. Under terms of the Swiss Federal Council ordinance of December 23, 1971, it can apply only to watches with: -Swiss Movement -Assembled in Switzerland -Final inspection must be done in Switzerland.
SWISS MOVEMENT: in order for a watch to state that it has Swiss Movement it must: -be assembled in Switzerland -be tested in Switzerland -have 50% of the parts from Swiss origin.
TACHYMETER: instrument for measuring speed over a measured distance. A racing car covers 1 mile in 30 seconds. The sweep second hand, when stopped at the end of the mile, would point to the 120 on the tachymeter. The average speed in 120mph.
TELEMETER: stopwatch or chronograph function with a scale that measures the distance of something from the wearer of the watch through the amount of time it takes for sound to travel.
TIDEGRAPH: tides are the periodic rise and fall of the water of oceans, seas, bays and other bodies of water caused mainly by the gravitational interactions between the Earth, Moon and Sun. Tides rise and fall about every six hours. The tide graph indicates tidal movement based on the Moon's transit over the meridian and the lunitidal interval. (Also called Tide Function).
TIME ZONE: the world is divided into 24 time zones spaced at intervals of 15 degrees in longitude. The zones start at 0 with Greenwich. Within each time zone, the hour and minute of the day is defined to be the same. Time zones are usually specified by the number of hours they differ from GMT. EST is GMT 5 hours.
TITANIUM: a metal, grey in colour, that is used for watch cases and bracelets. Much stronger and lighter than stainless steel and hypo-allergenic. It is 30% stronger and 50% lighter than steel. It is very resistant to salt water corrosion, making it useful for diver's watches. Although, since it can be scratched easily, some manufacturers use a coating to resist scratching.
TITANIUM CARBIDE: a black treatment, like DLC, it is very scratch resistant, and it is harder than PVD.
TOURBILLION: A tourbillon is found in mechanical watches and is a device that eliminates timekeeping errors caused by the small differences in the rates a watch runs in the vertical and horizontal positions. It consists of a round cage, holding the balance and escapement. It rotates continuously at the rate of one rotation per minute.
UNI-DIRECTIONAL BEZEL: a bezel that can only rotate only one way.
VPH: (Vibrations Per Hour) movement of a pendulum limited by 2 extreme positions. The balance of a mechanical watch generally makes 5 or 6 vibrations per second (18,000-21,600 per hour.) A high frequency watch makes 8-10 vibrations per second (25,200/28,800/36000/43,200 per hour) The higher the number the smoother and more accurately the watch will run. (same as BPH "beats per hour").
WATER RESISTANCE: The ability of a watch to withstand water from entering the case. Water resistance is generally measured in four ways, where (1 ATM = 1 BAR = 10 METRES = 33.3 FEET).
WHEEL: (or pinion) circular part revolving an axis to transmit power or motion. Centre wheel, front wheel, hour wheel, minute wheel, third wheel, transmission wheel.
WORLDTIMER: 24 different time zones that can display the current time in any part of the world, without adjusting the crown.