Glossary Of Common Watch Terms

 

A

 

Accuracy: This is the rate constancy of a watch, whether it is showing the exact time or not. An accurate watch gains or loses the same amount every day.

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.Adjusted (i.e. 

Adjusted 5 positions: During manufacture an adjusted watch is calibrated to keep accurate time under various conditions. There are 9 basic adjustments. Stem up, Stem Down, Stem Left, Stem Down, Face up, Face Down, Heat, Cold, and Isochronism.

Alarm: Mechanical A watch that will give an audible or vibrate at a pre-set time. Mechanical alarms have an extra hand for setting time of an alarm. Inside there is usually a second mainspring that powers a small mechanism that makes a tiny weight vibrate back and forth causing both a noise and the watch to vibrate at a designated time. 

Altimeter: This provides the altitude by responding to changes in barometric pressure. The altimeter can usually be found on pilot watches.

Analogue: A term used to describe a watch that has hands versus a digital display.

Anti-Magnetic: A watch that has been manufactured to resist becoming magnetized. (Watches that become magnetized may not keep accurate time because the magnetism interferes with the function of internal parts)

Aperture: Small opening in the dial, such as the ones used for displaying the day and date. In "jump hour" watches the Aperture will be used for displaying the time. 

Arabic Numerals: 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 Roman Numerals I,II,III,IV,V,VI,VII,VIII,IX,X,XI,XII

Automatic: A watch that is wound by the everyday movements of the wearer. A tiny rotor turns and swings with whenever the watch is moved.  This in turn rotating a tiny gear which ratchets the larger mainspring gear one click at a time. The system was invented in Switzerland by Abraham-Louis Breguet in the 18th century and was first used in a wrist-watch by John Harwood.

Auxiliary Dial: A smaller extra dial within the main dial. Example: Seconds dial. 

 

B

 

Battery EOL: Battery End Of Life indicator. This function forewarns of impending battery failure in a quartz watch by means of the second hand jumping in two or sometimes four second intervals. The wearer usually has approximately two weeks before battery failure.

Bezel: The bezel is the topmost ring of the watch, surrounding the dial of the watch. A bezel may be fixed or in the case of a diver's watch, rotating. It can either be plain (usually fixed) or can be marked with, for example a 0-60 minute scale in the case of divers' watches. Older rotating bezels were usually bi-directional, modern diving watches are equipped with a unidirectional bezel.

Blued Screws: Traditionally, high quality movements were fitted with screws which were artificially blued, more for decoration than function. 

Box Hinge Case: A case with heavy reinforced hinges and heavy metalwork supporting the bow/pendant

Bracelet: Another term for a metal watch band made of elements that resemble links. 

Bridge(s): These are metal plates with "jewels" that hold rotating watch gears. Much like columns between two floors of a building. 

 

C 

 

Calendar: A watch that shows the day of the month, and often the day of the week and the year. There are several types of calendar watches 

Caliber or Calibre: A number and letter designation that identifies a watch movement. Example: "Elgin 673".

Case: The metal housing of a watch's internal parts or movement. 

Chronometer: A timepiece that has met certain high standards of accuracy set by the Controle Officiel Suisse des Chronometeres in Switzerland. 

Complicated Watch: ACalend watch with other functions besides timekeeping. For example, a chronograph is a watch complication. Other complications coveted by watch collectors include minute repeaters, tourbillions, perpetual calendars, and split-second chronographs. 

Countdown Timer: A function that lets the wearer keep track of how much of a pre-set period of time has elapsed. 

Crown: Round metal cap that is used to wind and set a watches time and calendar.

Cuvette: Inner dust cover on a watch case.

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.

Chronograph: A chronograph is a mechanism for measuring short time spans independently of the normal timekeeping function. Many mechanical chronographs measure up to 12 hours with indicators for seconds, minutes (usually to 30) and hours.

Chronometer: Movements which meet specific timekeeping criteria laid down by the Swiss Official Chronometer Control are awarded a Chronometer Certificate. Movements are usually tested out of the case for 15 days and nights in various positions and at various temperatures.

Crown: The crown, often referred to as the winding crown or winder is used for winding the watch in the case of a non-automatic, for setting the hands to the correct time and often for setting the date in the case of calendar equipped watches. 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.

Crystal: The crystal is the clear cover over the dial. Can be referred to as the glass. Various materials have been used over the years including acrylic, mineral (glass) and sapphire. 

Clasp: The part of the watch that connects the two ends of the bracelet or strap together. 

 

D 

 

Dial: Face of a watch with hour indicators.

Dual Tim/Dual time zone watch: As the name indicates, this watch tells time in two locations around the globe.

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.

Dial: The dial, often referred to as the face is usually marked with numbers or batons to which the hands point in order for the wearer to tell the correct time. Dials themselves can be very simple, sometimes with no markers at all or extremely complex as in the case of pilots' chronographs. Dials can be decorated with patterns or in some cases with precious stones.

Digital Display: As opposed to an analogue display, a digital display shows the time in numbers. Most often used with LCD displays in the case of a quartz watch, during the 1960's there were many mechanical digitals with rotating discs instead of hands. Cut outs in the dial would show the correct time. The first quartz digital watches came onto the market in the early/mid 1970s; for example the Pulsar Time Computer.

Diver's Watch: Divers' watches traditionally are large, featuring a graduated rotating bezel and often a screw down winding crown. Water resistant to 200m as a minimum, the modern diver's watch must confirm to certain standards laid down for example by ISA in order to be classified as a Scuba Divers Watch. 

 

E 

 

Ebauche: A watch movement manufactured with the purpose of being assembled into a completed watch elsewhere. Many "no name" watches are called ebauche. Many times the movements, dials, hands, and cases were all manufactured by separate makers and later assembled.

Engine Turning: Decorative engraving, usually on the watch face. 

Escapement: The escapement in a mechanical watch refers to a combination of parts including the anchor, pallets and balance wheel amongst others which translate the power of the mechanism into regular timekeeping. The escapement is responsible for the familiar ticking sound of a mechanical watch. 

 

F 

 

Face: See Dial. 

Fob: Watch Chain.

Flyback Hand: A second hand on the chronograph that can be used to time laps or to determine finishing times for several competitors in race. When reset, the second hand zips back to zero very quickly – Hence the term "fly back"

Flyback: This phrase is often 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. 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.

Frequency: Amplitude, in the case of mechanical watches refers to how many times an hour the watch goes tick for a given time period! It is often referred to as half-swings per hour or beats per hour (BPH). Thus a watch beating at an amplitude of 28,800 per hour ticks 8 times per second. 

 

G 

 

Gear Train: The system of gears in a watch. Some were made of solid gold to avoid magnetism, therefore making them more accurate.

Gilt: Gold plating

Gold plating: A layer of gold that has been deposited onto a metal.

Gold Filled/Rolled Gold Plate: This is a term used to describe early method of gold plating on watch cases and other watch parts (buckles, bracelets etc). A thin sheet of solid gold would be heated and pressed onto a base metal.

Gold Jewel Setting: In high grade watches the jewels were mounted in solid gold settings.

Gear Train: The gears used in a mechanical watch which run from the mainspring which powers the watch through to the escapement which translates that power into timekeeping.

Geneva Stripes: A form of decoration in higher grade watch movements which look like stripes on the movement plates. These used to be applied by hand; in many cases in modern times, they are very simply applied by machine.

Guilloche: A form of decoration for watch dials, giving the dial great depth. Often applied to silver or silvered dials. 

Gasket: A seal generally made from rubber or plastic, which helps to protect the internal mechanism of the watch from dust, water, and other types of moisture. 

 

H 

 

Hair-Spring: see Balance Spring

Hallmark: Stamp indicating origin or metal content (gold, silver, platinum)

Horology: The study of time and timepieces. 

Hunter/Hunting Case: Pocket watch case that completely incases the watch. Has a front cover and a back cover to protect the watch (while hunting)

Handwind/Handwound: Simply describes a watch with a mechanical movement which needs to be wound by the wearer using the winding crown. This winds the mainspring up which then releases its energy to power the watch.

Hack/Hacking: Describes the feature of a movement whereby the seconds hand can be stopped for exact setting of the time. Originally a military term for this feature. 

Hands: The apparatus anchored in the center of the watch face that indicates the time. 

 

I 

 

Incabloc: Shock absorber system used to protect a watch's balance staff from breaking if dropped.

Isochronism: Meaning the watch runs at the same rate whether the watch is fully wound, or only partially wound. 

Index/Indices: Usually refers to the markings on the dial of a watch showing hours and minutes. Can however refer to the markings on the regulator of a watch movement to aid precision adjustment for accurate timekeeping. 

 

J 

 

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 handwound mechanical usually comprises 17 jewels which in the main is the optimum count. Automatics may require more for the winding mechanism itself. In the 1960s there appeared to be a competition to see who could fit the most jewels in a watch movement, manufacturers proudly referred to 100 Jewels on the dial; opening the watch usually revealed that up to 80% of these jewels had no purpose and were simply mounted here and there on the movement to up the jewel count!

Jumping Hour: System of timekeeping whereby the seconds and minutes are shown by traditional hands but the hour is shown in a dial cutout (often at 12), on the minutes hand reaching 59 minutes, the hour disc under the dial will jump to the next hour. 

 

K

 

Key Set: Watch that is set by means of a small key instead of by a crown. Earlier watches were key-set.

Kif: A trade name for a shock absorbing system; in a similar vein to Incabloc above. 

 

L 

 

Lever Set: To avoid being set (incorrectly) by accident, Railroad watches were always lever set watches. This meant the conductor would need to remove the crystal and pull out a small lever in order to adjust the time. This was a serious safety measure to avoid train collisions.

Lugs: Projections on the watch case to which the watch band/bracelet is attached. 

LCD Display: Or Liquid Crystal Display; used for the display on most modern digital watches. Followed from the earlier LED or 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.

 

M 

 

Mainspring: When wound this spring stores energy and is the driving force that runs a watch. 

Mechanical movement: A movement powered by a mainspring, working in conjunction with a balance wheel. 

Micron: Unit of measure of the thickness of the gold-plating. 1 micron = 1/1000mm. 

Moon-phase: A window in a watch face that shows the current phase of the moon. 

Movement: Simply used to describe the workings or engine(!) of a watch, be it mechanical or quartz. Often referred to as a calibre by manufacturers.

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. 

 

N

 

Nivarox/Nivaflex: Trade names for the metal alloy used for many Swiss watch mainsprings and hairsprings. These materials self compensate for the effects of temperature (e.g. expansion and contraction), are extremely strong and corrosion resistant. 

 

O

 

O-Ring: O rings are used to seal the backs of watches which feature either a press-in back or a screw on back. They ensure water resistance. Usually also used on the winding stems of watches and in the winding crowns to protect against the ingestion of water and dust. Normally made from a rubber/plastic compound. 

 

P 

 

Pair Case Watch: A Pocketwatch with that sits inside another protective case. The watch inside also having its own case. Hence pair case.

Pendant: The neck of a pocketwach. This is where the crown is located and the bow is attached.

Plate: A watch has a front and a back "plate" . The internal parts are held between.

Position: i.e. "adjusted 3 positions". This term refers to the testing performed on a watch to determine its accuracy in different positions. There are 6 potential positions that a watch can be adjusted to perform under. They are Dial up, Dial Down, Stem up, Stem Down, Stem Left, Stem right. 

Platine: Platinum

Power Reserve Indicator: A feature of a mechanical watch that shows how much longer the watch will operate before it must be wound again. 

Power Reserve: 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). 

Perpetual Calendar: A watch calendar that automatically adjusts for the different lengths of the months and leap year. 

 

Q

 

Quartz: Used to describe a watch powered by an oscillating quartz crystal which draws its power from a small battery. Oscillating 32,768 times per second, an electronic circuit divides this oscillation into precise increments of 1 second or less. Used in both digital and analogue watches. Whilst derided by many purists as disposable and of little soul, the quartz watch is nonetheless extremely accurate. Watches have been made super-accurate by using a much higher frequency (e.g. 4.2 million cycles per second) or by using two oscillators and by using temperature compensation. 

 

R 

 

Repeater Watch: A complicated watch that chimes out the current time when the wearer pushes a button. 

Roman Numerals: I,II,III,IV,V,VI,VII,VIII,IX,X,XI,XII

Rotating Bezel: A bezel (the ring surrounding the watch face) that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions. 

Rotor: A special weight in an automatic watch that rotates with the movement of the watch wearer and winds the movement's mainspring. 

Rattrapante: used to describe the split seconds chronograph (see Flyback) which has two seconds hands sitting atop one another. 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.

Register: Another name for a sub-dial; this is usually a dial within the main dial of a watch. The best example is possibly a chronograph where there may be registers for the chronograph minutes and hours. Some watches have registers with pointers showing the day and date.

Retrograde: Used to describe a pointer hand on a watch dial (often a sub-dial) which returns to zero at the end of a prescribed period. For example a watch may have retrograde date – in this case the hand moves up a scale a day at a time, pointing to the current date – when it reaches 31 it will spring back to 1

 

S 

 

Selfwinding: See automatic watch.

Shock Absorber: A watch with an "Incabloc" spring on the balance.  This is a small spring which holds the balance staff jewel in place and prevents the delicate staff from breaking under shock.

Shock Resistance: 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. 

Silveroid: Metal compound made to resemble silver.

Skeleton watch: A watch case with a transparent front or back that allows the wearer to view the watch's movement. 

Slide Rule: A device usually on chronograph watches that allows the owner to perform complicated logarithmic or other calculations on the outer edge of the watch face.

Spring Bar: Bar which holds a watch strap to the case.

Staff: The axle of the Balance

Stainless Steel: An extremely durable metal resistant to stain & rust. 

Sterling: Sterling silver refers to silver that is 92.5 percent pure, which should be stamped on the metal

Subdial: A small dial on the watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on the chronograph, or indicating the date. 

Sapphire Crystal: Synthetic sapphire formed for use as the crystal of a watch. Extremely scratch resistant (9 on the Moh scale), a sapphire crystal is the material of choice for many watch collectors. The downsides are that sapphire can chip at the edges if they protrude and can shatter.

Screw Crown: A watch winding crown which screws tightly to the case of the watch on a tube; the purpose is to ensure extreme water resistancy.

Sub-Dial: See Register above; a dial within or on the main dial of a watch. 

Strap: Also referred to as a watchband, this is the part of the watch that goes around the wrist to secure it and is usually made of leather or plastic. 

 

T 

 

Tank Watch: A rectangular watch that resembles that shape of the track and body of a military tank as viewed from above.

Tonneau Watch: A watch shaped like a barrel, with two convex sides. 

Tourbillon: A device in a mechanical watch where the escapement is mounted on a platform which rotates.  This eliminates positional timekeeping errors.

Train: see Gear Train. 

Tachymeter: A scale used to measure units per hour. Commonly found on the bezels of chronograph watches, an event is timed by using the chronograph seconds hand. The hand is stopped when the event ends and the hand will point to the number of units per hour that could be achieved.

Tritium: An isotope of hydrogen used in the luminous compounds which give watch dials and hands their glow in the dark capabilities. Many watch dials will show a small T at the bottom, indicating the use of tritium. The half life of tritium is 12.5 years thus it will lose its ability to provide illumination as time passes. Now largely superceded by non-radioactive organic compounds such as the trade name Luminova. 

 

U 

 

Unidirectional Rotating Bezel: Rotating bezel, often found on divers' watches, that moves only in one direction to avoid being bumped and reset.  Designed to prevent a diver overestimating his or her remaining air supply. 

UTC: Universal Time Co-ordinated. 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 Co-ordinated(UTC).. GMT as such is now obsolete however, being replaced by UTC. Using this timezone/standard avoids errors and problems associated with different timezones and summer times operational in different countries. 

 

W 

 

Winding Stem: The stem is an internal part of the watch to which the crown is attached. 

Water Resist/WR: Watches have varying degrees of water resistancy, ranging from WR30 Meters to some specialist watches having a capability of withstanding water to 10000 Meters. The usual for a diver's watch is 200m whilst 100m would be suitable for everyday swimming.

Winder/Winding Crown: Same as Crown, above. Used for winding the watch and setting time/date. 

Water Resistant: The ability of a watch to resist penetration by water up to certain water pressure depths. Most watches are "water resistant" but not necessarily "water proof." 

 

Z

 

Zulu Time: Yet another reference to GMT and UTC! The use of this phrase is prevalent in civil aviation and military. Why Zulu? Well, Zulu is the phonetic for Z and the Z is for the Zero meridian, being that meridian passing through Greenwich.