Glossary A-Z
A
ALARM :
A device that sounds a signal at a predetermined time.
ALTIMETER :
A device that determines altitude by responding to changes in barometric pressure.
ANALOG DISPLAY :
A display that shows the time by using hands and a dial.
AUTOMATIC WINDING :
This referred to winding that occurs through motion on the wearer’s wrist, rather than through winding the watch manually. An automatic watch that isn’t worn for a couple days will need to be wound again to get started again.
APERTURE :
A small opening in the dial that displays certain information such as date, day, month or moon-phase.
ANTI-MAGNETIC :
A device that is not affected by magnetic fields.
ATM – ATMOSPHERE :
One atmospheric pressure corresponds to the pressure at sea level, with the following equivalence:
1 ATM = 1 BAR = 10 meters = 33.3 feet.
B
BAND :
A ring on your finger, or a group who plays music. When referring to watches, it is referred to as a bracelet or strap; not as a band.
BALANCE :
The heart of a mechanical watch movement. The mainspring provides the energy and the balance (coupled with the hairspring) swings to divide time into equal parts.
BALANCE SPRING :
A very small spring in a mechanical watch that returns the balance wheel back to its neutral position.
BALANCE WHEEL :
A part of a mechanical watch that oscillates and divides time into equal portions.
BEZEL :
The ring around the crystal on the top portion of a watch. It is usually made of metals such as gold, gold-plate, platinum or stainless steel. It holds the glass or crystal in place.
BI-DIRECTIONAL ROTATING BEZEL :
A bezel that can be moved either clockwise or counter-clockwise. Used to make mathematical calculations or keeping track of elapsed time.
BIENFACTURE :
A Swiss word that refers to the high quality of a piece of work or an object. In French, it means “to make well”.
BAR :
thin 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 springs tension controls the amount of energy transmitted to the measurement. Hooked to the barrel and arbor, when it is tensed it releases energy.
BEAT :
the number of times per second (BPS) 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.
BEVEL :
furrow or groove cut at an angle that is either over or under, but not equal to 90 degrees.
BEZEL :
the ring around the top of the crystal. Generally 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.
BOTTOM PLATE :
supports the bridges, which are often on the top of the plate, the movement, the dial, and the holes where the jewels are inserted.
BRACELET :
metal linked 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 2oclock and/or 4oclock on the dial to control specific functions such as the chronograph or the alarm.
C
CALENDAR :
A feature that shows the day of the month, and often the day of the week. Some calendar watches show the date on sub-dials while others use a scale on the outside edge of the watch dial.
CALIBER :
Also known as calibre, the caliber is the size or style of a watch movement.
CASE :
The container that protects the watch movement. It also gives the watch an attractive appearance. Cases come in many shapes, round, square, oval, tonneau and rectangular.
CASEBACK :
The underside of a watch that lies against the skin. Some casebacks are made of crystal allowing you to view the watch movement.
CERAMIC :
used as a shield for spacecraft reentering the earths atmosphere, high tech ceramic is polished with diamond dust to create a highly polished finish. Usually found in black, white and Grey. The watch brand most readily associated with pioneering the use of ceramics in watchmaking is Rado. Check out the RADO collection.
CHRONOGRAPH :
A time that can be started and stopped to time and event.
CHRONOMETER :
An instrument for measuring time very accurately. For a Swiss watch to be called a chronometer, it must meet very high standards set by the C.O.S.C. (Controle Officiel Suisse des Chronometres). The requirements are 15 days and nights at five different positions and temperature changes.
CLASP – BUCKLE :
Used to secure the strap or bracelet of a watch. There are three types of clasps:
Folding Clasp, Butterfly Clasp, Jewelry Clasp
COTES DE GENEVE :
A regular wave pattern obtained by engine-turning and polishing.
COUNTDOWN :
Time remaining in a predefined period.
C.O.S.C. Controle Officiel Suisse des Chronometres:
The official Swiss Chronometer Testing Institute, which inspects and certifies watch movements. Each test includes the movement’s performance in five (5) different positions and three (3) different temperatures. Any watch that successfully passes this test is awarded the title Chronometer.
CROWN :
A button, often fluted, on the outside of the watch case used to wind the mainspring in mechanical watches. It is also used to set the time, when pulled out, and for setting a watch calendar. A screw-down crown is used to make the watch more water resistant and to help keep out dust.
CRYSTAL :
A transparent cover that protects the watch dial. Crystals are made of glass, plastic or synthetic sapphire. Non-reflective coatings on some crystals prevents glare. (See also: Mineral Crystals, Plastic Crystals, Sapphire Crystals)
CYCLOPS :
A small lens on the crystal to magnify the date.
D
DAY-DATE :
A watch that indicates the day of the week as well as the date.
DAY/NIGHT INDICATOR :
A colored or shaded band on a world time watch, which shows the time zones that are in daylight and those in darkness.
DEPLOYANT BUCKLE :
A buckle that fastens to the watch strap and opens and fastens using hinged extenders. Invented by Louis Cartier in 1910. A deployant buckle is easier to put on and remove than a tang buckle. Deployant comes from the verb “deployer” which means to unfold. Do not mistakenly refer to it as a “deployment” clasp. This safety feature also ensures the watch won’t drop when putting it on your wrist.
DESTRO :
In Italian, it translates to “right”. It means that the watch was intended to wear on the right hand, and is most commonly associated with High end Swiss made watches.
DIAL :
A plate, with a metal base and visible through a crystal, that carries certain indication, such as the hours, minutes and sometimes seconds.
DIGITAL WATCH :
A watch that shows the time through a numerical display instead of via a dial and hands (analog watch).
DEPTH ALARM :
A complication in a diver's watch that sounds an alarm when the wearer exceeds a pre-set depth. The alarm stops when the diver ascends above the pre-set depth.
DIAL :
The face of the watch, where the time and other indicators are displayed.
DIGITAL :
A watch that uses an LCD or LED screen to display the time.
DISPLAY BACK – OPEN BACK :
A transparent case back that allows the movement to be viewed.
(Also known as: clear back, see-through back, skeleton back, exhibition case back).
DIVE WATCH :
A watch specifically designed and built for divers, with high resistance to pressure and water. Specialized dive watches include chronometers, decompression alarms, and other functions useful for diving.
DLC (Diamond Like Carbon):
A metal coating that creates a grey/black finish, highly scratch-resistant and corrosion-resistant. This coating is similar to PVD but is even harder and more expensive.
DUAL TIME ZONE :
A watch function that displays local time as well as the time in another time zone.
E
ESCAPEMENT :
A device in a mechanical watch that controls the motion of the hands by controlling wheel rotation.
ETA :
The leading manufacturer in Switzerland for movements used in many Swiss brands. One of the big third-party movement manufacturers. Owned by Swatch Group, parent company of Omega, Longines and Tissot, it also produces movements for dozens of other Swiss brands.
F
FLANGE :
A ring made of various materials (usually plastic) that seals the gaps between the case/frame and the case back or crystal to ensure water resistance.
FLYBACK :
A chronograph function that allows the stopwatch to be reset to zero without stopping it first, enabling quick successive timing.
FREQUENCY :
Refers to the operating frequency of an automatic watch, measured in vibrations per hour (VPH) or beats per hour (BPH). 18,000 VPH = 2Hz, 21,600 VPH = 3Hz, 28,800 VPH = 4Hz, 36,000 VPH = 5Hz,
43,200 VPH = 6Hz, 72,000 VPH = 10Hz
FULL ROTOR :
Automatic watches with rotors that rotate 360 degrees in both directions to wind the movement efficiently.
FUNCTION :
In mechanical watches, it is called a complication, but in quartz watches, it is technically referred to as a function.
G
GASKET :
Most water-resistant watches are equipped with gaskets to seal the case-back, crystal and crown from water infiltration. Gaskets should be checked every couple of years to maintain water resistance.
GEAR TRAIN :
A system of gears that transmit power from the mainspring to the escapement.
GOLDPLATING :
An electro deposited layer of gold with the thickness is measured in microns. “GP, HGE, GE” or any fraction after a number are stamps indicating gold plate.
GREENWICH MEAN TIME - GMT (Or Dual Time) :
A watch that displays a second time zone, usually indicated by an additional central hour hand. The standard for which all other 23 time zones are based off of and sometimes referred to as UTC.
GRAND SONNERIE :
A repeater that sounds the hours and quarter hours by pressing a lever.
GUILLOCHE :
Surface decoration or texture. An even pattern is cut, usually on the dial.
H
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 year of manufacture, the identity of the cases maker, trademarks, reference numbers, and/or serial numbers.
HAND :The indicator that moves over the dial to point at the hour, minute or second. Watches generally have three hands to show the hours, minutes and seconds. Hands can have very different shapes: pear, Breguet, sword, skeleton, baton, arrow, etc.
HAND-WOUND WATCH :
a watch that receives energy by hand winding the crown.
HARDBACK :
a solid metal caseback.
HELIUM ESCAPE VALVE :
Prior to surfacing from great depths in a pressurized enclosure, such as diving bell, toxic gases that have been formed in the enclosure are removed and helium is mixed into the air. The helium molecules are lighter than air and can therefore penetrate the watch. When the pressurized enclosure surfaces and is depressurized the helium rushes out of the watch so quickly that the glass on the watch pops out as well. The watch was built to withstand external pressure, not internal pressure. The glass popping out can be avoided by opening the Helium Escape Valve on the watch during resurfacing, which allows the helium to escape but prevents water from entering the watch.
HOROLOGY :
The science of the measurement of time.
HOUR MARKERS :
Arabic numerals, Roman numerals or symbols placed around the dial to mark the hours.
HUNTER POCKET WATCH :
A pocket watch with a cover, which is distinguished by a winding stem at 3 o’clock.
INCABLOC :
a brand of shock absorber for mechanical watches designed to protect pinions or jewels.
INDEX OR HOUR MARKER :
Used instead of Arabic or Roman numerals to indicate hours. Can be painted, applied (by hand), filled with or made from luminescent material, or made from exotic materials, such as diamonds.
INTERNAL BEZEL :
a bezel inside the watch case usually with a separate or additional crown.
J
JEWELS :
Traditionally rubies, now usually synthetic stones with very smooth surfaces, jewels are used to hold moving parts in place with minimal friction.
L
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.
LUGS :
Sometimes referred to as horns, lugs are projections on the watch case. There is a spring bar between the the lugs that is used to fix the strap or bracelet to the case.
LUMINESCENCE :
Luminescence refers to emitting rays of light. A luminescent material is deposited on numbers and hands in order to read the time in the dark.
M
MAINSPRING :
Contained in the barrel, the mainspring is the driving flat-coiled spring of a watch that supplies power.
MANUAL-WINDING :
a hand wound mechanical watch.
MANUFACTURE :
A watch company that uses at least one of its own movements that has been manufactured in house.
MILANESE BRACELET :
A metal bracelet made from thousands of small links, woven together to create a fine, supple mesh.
MINERAL CRYSTALS :
Heat hardened glass about ten times harder than plastic. Extremely scratch resistant but must be replaced if they do scratch.
MECHANICAL MOVEMENT :
A mechanical movement is powered by a main-spring and works with the balance wheel.
MOVEMENT :
The inner mechanism of a watch that keeps time and powers the watch’s functions.
MOON PHASE :
A sub-dial display that continuously tracks and shows the current phase of the moon as it moves through its cycle.
P
PALLADIUM :
a rare and lustrous metal that is slightly 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.
PALLET :
meshes with the teeth of the escapement wheel and transmits an impulse to the balance.
PERPETUAL CALENDAR :
A calendar complication that adjusts the watch’s calendar for the varying length of months as well as leap years.
PLASTIC CRYSTALS :
Plastic crystals are soft and flexible so they resist small impacts, enabling surface scratches to be buffed out.
POWER RESERVE INDICATOR :
A feature of a mechanical watch that shows the remaining power in a watch movement, indicating the length of time until the timepiece will need to be wound again.
PVD (Physical Vapor Deposition) :
method of coating watch cases by integrating titanium particles and then depositing gold for color. Generally comes in black finish, but other colors can be created. (Very similar to "titanium carbide".)
Q
QUARTZ MOVEMENT :
Quartz movements use a battery-powered system of electronics to keep track of time. Typically, quartz movements are cheaper and more accurate than their mechanical equivalents.
R
REGULATOR :
A part of the movement that makes time more accurate by regulating beats by speeding them up or slowing them down.
REPEATER :
A device that chimes the time upon depressing a slide lever.
RETROGRADE HAND :
A hand with a tip moving over a portion of the arc of a circle instead of an entire circle. When it reaches the end of its path, it instantly returns to its point of departure.
ROTOR :
Part of an automatic watch that winds the mainspring by constantly rotating.
ROMAN NUMERALS :
The old-school way of showing the hours using the Roman system of numerals, and an alternative to Arabic numerals and indexes/hour markers. See also Arabic numerals and Index or hour marker.
S
SAPPHIRE CRYSTALS :
Sapphire crystals are 2-3 times harder than mineral glass and virtually scratch-proof. They are more brittle so are more likely to crack or shatter than mineral. Replacement cost is substantially higher than for mineral crystals.
SCREW BACK :
The back of the case has a thread so that it can be screwed into the case.
SCREW-DOWN CROWN :
A crown that screws down into the case to make the watch more water resistant and to help keep out dust.
SHOCK ABSORBER :
Resilient bearing in a watch that is intended to take up the shocks received by the balance staff and protect its delicate pivots from damage.
SHOCK RESISTANCE :
A watch’s ability to withstand an impact equal to being dropped onto a wooden floor from a height of 3 feet.
SKELETON WATCH :
The case, dial and various parts of the movement have been cut away allowing the main parts of the watch to be seen. A crystal is mounted on both the front and back of the watch.
SLIDE RULE :
A rotating bezel that can multiply or divide two numbers, convert miles/KM, convert exchange rates, etc. An example is a dollar to Euro converter to calculate rate of descent or fuel consumption for pilots.
SMALL SECONDS DIAL :
The seconds are displayed by a hand in a small subsidiary dial and not from the center of the timepiece.
SPLIT SECONDS CHRONOGRAPH :
A watch that possesses two hands, one of which can be stopped to indicate an intermediate time while the other hand continues to run.
SPRING BAR :
A spring loaded metal bar mounted between the case lugs (horns) used to attach a strap or bracelet.
STAINLESS STEEL :
An extremely durable metal alloy composed of steel, nickel, and primarily chromium. It is highly resistant to rust and magnetization. The most commonly used grade in watchmaking is 316L stainless steel. Some watch manufacturers use harder and more resistant types, such as 904L stainless steel, which is generally used in chemical applications and is significantly more expensive than 316L.
STANDARD TIME :
The time that is kept locally in each of the time zones when it is not daylight savings time.
STEM :
The shaft that connects to the movement’s winding mechanism. The crown is fitted on the opposite end.
STRAP :
A strip or band of leather or rubber that holds the watch to the wrist. It must be non-metal to be considered a strap; a metal version is referred to as a bracelet.
STOP SECOND :
(same as hacking) crown which can be pulled out to set the seconds on a watch accurately.
SOLAR POWERED:
A watch powered by light, which collects and converts light into energy to run the movement.
SUB-DIAL :
A small dial placed inside the main dial on a watch’s dial. Watches can have as many as four sub-dials (auxiliary dials). They give information not provided by the main watch dial such as chronographs, alarm, dual time zone, and calendar.
SWEEPING SECONDS HAND :
A second hand that is mounted in the center of the dial, instead of a sub-dial, and “sweeps” the entire dial of the watch.
SWISS MADE :
A watch can only be considered to be Swiss made if, (1) its movement is Swiss; (2) its movement is cased up in Switzerland and (3) the manufacturer carries out the final inspection in Switzerland.
SWISS MOVEMENT:
For a movement to be officially classified as Swiss Movement, it must meet the following criteria: It must be assembled in Switzerland, it must be inspected in Switzerland, at least 50% of its components must be of Swiss origin.
SUPER LUMINOVA :
The brand name of a high-quality luminescent material used by most brands when creating watches that can be read in low-light conditions.
T
TACHOMETER :
A tachometer, also referred to as a tachymetre, is a graduation on dial of a chronograph which enables one to determine average speeds or hourly production on the basis of an observation period of under sixty seconds.
TANG BUCKLE :
Conventional feed through buckle (like a belt buckle).
TIME ZONES :
Time zones refer to the twenty-four regions or divisions of the globe. Our time zone here in Minnesota will be indicated by either Chicago or Mexico City.
TITANIUM:
Titanium is used in the construction of watch bracelets and cases. It has several advantages over stainless steel: 30% harder than steel, 50% lighter than steel , Hypoallergenic, making it skin-friendly. And is Highly resistant to seawater corrosion, ensuring long-term durability.
THREE HANDER :
Term used to describe a watch that only tells the time.
TONGUE :
A tonque, or tang, is a movable metal piece in a buckle which penetrates the holes in a leather strap
TONNEAU WATCH :
A watch shaped like a barrel with two convex sides.
TOURBILLON :
A device that eliminates errors in timekeeping by balance the horizontal and vertical positions of the balance wheel.
TRITIUM :
A slightly radioactive substance that collects light and is used to allow the hands or hour markers to glow in the dark. The radiation is so low that there is no health risk. Watches bearing tritium must be marked as such, with the letter T on the dial near 6 o’clock.
U
UNI-DIRECTIONAL ROTATING BEZEL :
A bezel that indicates elapsed time, often found on divers watches. It moves only in a counter-clockwise direction. If a diver is timing his remaining air supply and knocks the bezel by mistake, it can only move in one direction so that the error will only be on the side of safety.
V
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) Vibrations per hour is also called BPH ("beats per hour").
W
WATER RESISTANCE :
The ability of a watch to withstand (resist) splashes of water on the timepiece. This will indicate the depth that a watch can be worn underwater.
WHEEL :
Also referred to as a pinion, the wheel is a circular part that revolves around an axis to transmit power.
WINDING :
Winding is the action of tightening the mainspring of a watch. This is done by hand (turning the crown) or automatically (by the motion of the rotor).
WORLDTIME:
A watch function that displays the time for all 24 time zones. Each time zone is represented by the major cities within that zone.
Y
YACHT TIMER:
A countdown chronograph specifically designed for timing sailing races, often featuring audible signals to mark key intervals.