Watch Terminology 101
Alarm: A device that sounds a signal at a pre-set time.
Altimeter: A device that determines altitude by responding
to changes in barometric pressure.
Analog Display: A display that shows the time by means of hands
and a dial.
Analog Watch: A watch with a dial, hands, and numbers or
markers that present a total display of 12-hour time span. Analog digital
refers to a watch that has both a digital display and hands of a conventional
watch.
Aperture: Small opening. The dials of some watches (in
French: montres à guichet) have apertures in which certain indications are
given (e.g. the date, the hour, etc).
Automatic Movement: A mechanical movement that requires no winding
because the rotor, part of the automatic mechanism, winds the mainspring every
time you move your hand. The first automatic movement was invented in
Switzerland by Abraham-Louis Perrelet in the Eighteenth century. When fully
wound and left to sit, most automatics have up to 36 hours of reserve power.
Mechanical movements are accurate within one minute each day. Automatic
movements have gained in popularity the last few years especially with watch
connoisseurs and are considered to be Switzerland's mechanical answer to the
popularity of the no-winding-needed quartz movements that are standard in
Japanese watches.
Auto Repeat Countdown
Timer: A countdown timer that
resets itself as soon as the preset time has elapsed and starts the countdown
again. It repeats the countdown continuously until the wearer pushes the stop
button.
Automatic Watch: A watch whose mainspring is wound by the
movements or accelerations of the wearer's arm. On the basis of the principle
of terrestrial attraction, a rotor turns and transmits its energy to the spring
by means of an appropriate mechanism. The system was invented in Switzerland by
Abraham-Louis Perrelet in the 18th century.
Automatic Winding: (also called "self-winding") Winding
that occurs through the motion of the wearer's arm rather than through turning
the winding stem. It works by means of a rotor that turns in response to
motion, thereby winding up the watch's mainspring. An automatic watch that is
not worn for a day or two will wind down and need to be wound by hand to get it
started again.
Balance Spring: A very fine spring (also called a "hair
spring") in a mechanical watch that returns the balance wheel back to a
neutral position.
Balance Wheel: The part of a mechanical watch movement that
oscillates, dividing time into equal segments.
Barrel: Thin cylindrical box containing the mainspring
of a watch. The toothed rim of the barrel drives the train.
Bezel: The ring, usually made of gold, gold plate or
steel, that surrounds the watch face.
Bi-directional Rotating
Bezel: A bezel that can be
moved either clockwise or counterclockwise. These are used for mathematical
calculations or for keeping track of elapsed time.
Bracelet: A type of watch band made of elements that
resemble links.
Bridge: Complementary part fixed to the main plate to
form the frame of a watch movement. The other parts are mounted inside the
frame.
Calendar: A feature 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: A term often used by Swiss watchmakers to denote
a particular model type, such as Caliber 48 meaning model 48. More commonly,
the term is used to indicate the movement's shape, layout, or size.
Cambered: Often used in referring to a curved or arched
dial or bezel.
Case: The metal housing of a watch's parts. Stainless
steel is the most typical metal used but titanium, gold, silver, and platinum
can also be used. Less expensive watches are usually made of brass and plated
with gold or silver.
Caseback: The reverse side of a watch case that lies
against the skin. May be transparent to allow viewing of the inner workings of
the watch or be solid. Most manufacturers engrave casebacks with their name,
water and shock resistance, case metal content and other details.
Chime: The bell-like sound made when a clock strikes on
the hour, half hour, etc. Two familiar chimes traditionally found in clocks are
the Westminster chime made by the famous Big Ben in London, and the bim bam, a
two note chime.
Chronograph: A stopwatch, i.e., a timer that can be started
and stopped to time an event. There are many variations on the chronograph.
Some operate with a center seconds hand which keeps time on the watch's main
dial. Others use subdials to elapsed hours, minutes and seconds. Still others
show elapsed time on a digital display on the watch face. When a chronograph is
used in conjunction with specialized scales on the watch face, it can perform
many different functions, such as determining speed or distance. Some
chronographs can time more than one event at a time. Do not confuse the term
"chronograph" with "chronometer". The latter refers to a
timepiece, which may or may not have a chronograph function, that's met certain
high standards of accuracy set by an official watch institute in Switzerland.
Watches that include the chronograph function are themselves called
"chronographs".
Chronometer: This term refers to a precision watch that is
tested in various temperatures and positions, thus meeting the accuracy
standards set by an official institute in Switzerland. Most watch companies
provide a certificate with your chronometer purchase.
Complication: A watch with other functions besides timekeeping.
For example, a chronograph is a watch complication. Other complications coveted
by watch collectors include: minute repeater, tourbillon, perpetual calendar,
or split second chronograph.
COSC: The official Swiss Chronometer Testing Institute
that puts every chronometer watch through a rigorous, 15-day testing procedure
to verify the watch's precision.
Countdown Timer: A function that lets the wearer keep track of
how much of a pre-set period of time has elapsed. Some countdown timers sound a
warning signal a few seconds before time runs out -- these are useful in events
such as yacht races, where the sailor must maneuver the boat into position
before the start of a race.
Crown: Button on the outside of the case that is used
to set the time and the calendar, and, in the mechanical watches, to wind the
mainspring.
Crystal: The transparent cover on the watch face made of
glass crystal, synthetic sapphire or plastic.
Day/Date Watch: A watch that indicates not only the date but
also the day of the week.
Day/Night Indicator: A colored or shaded band on a world time that
shows which time zones are in daylight and which in darkness.
Depth Alarm: An alarm on a diver's watch that sounds when the
wearer exceeds a pre-set depth. In most watches it stops sounding when the
diver ascends above that depth.
Dial: The watch face. In high-end watches the
numerals, indices and surface designs are applied as separate elements. In less
expensive watches, they may be simply printed on the dial.
Digital watch: A watch that shows the time through digits
rather than through a dial and hands display.
Direct-drive: A function that allows the second-hand to
advance in intervals rather than a smooth sweep for more precise timekeeping.
The French term for a direct-drive second hand is a trotteuse.
Dual Timer: 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, subdials, or other means.
Elapsed Time Rotating
Bezel: A graduated rotating
bezel used to keep track of periods of time. The bezel can be turned so the
wearer can align the zero on the bezel with the watch's seconds or minutes
hand. He/she can then read the elapsed time off the bezel. This saves him/her
having to perform the subtraction that would be necessary if he used the watch's
regular dial.
Engine turning: Decorative engraving, usually on the watch face.
Escapement: Device in a mechanical movement that controls
the rotation of the wheels and thus the motion of the hands.
Face: The visible side of the watch where the dial is
contained. Most faces are marked with Arabic or Roman numerals to indicate the
hours. Interestingly, when Roman numerals are used, it is traditional to use
IIII, rather than IV, to indicate the 4 o'clock position.
Flyback hand: A seconds hand on the chronograph that can be
used to time laps or to determine finishing times for several competitors in
race.
Gasket: Most water resistant watches are equipped with
gaskets to seal the case back, crystal, and crown to protect against water
infiltration during normal wear. It is important to have the gaskets checked
every two years to maintain the water resistance of the watch.
Gear train: The system of gears which transmits power from
the mainspring to the escapement.
Grande Sonnerie: A type of repeater that sounds the hours and
quarter hours when the wearer pushes the button.
Guilloche: A style of intricate engraving that is popular
on watch dials, usually very thin lines interwoven to create a surface texture.
Index: An hour indicator on an analog watch dial, used
instead of numerals.
Jewels: Synthetic sapphires or rubies that acts as
bearings for gears in the mechanical watch, reducing friction.
Jump Hour Indicator: A jump hour indicator takes the place of an hour
hand. It usually shows the hours by means of a numeral in a window.
Lap Memory: The ability, in some quartz sport watches, to
preserve in the watch's memory the times of laps in a race that have been
determined by the lap timer. The wearer can recall these times on a digital
display by pushing a button.
Lap Timer: A chronograph function that lets the wearer time
segments of a race. At the end of a lap, he/she stops the timer, which then returns
to zero to begin timing the next lap.
Liquid-Crystal Display: A digital watch display that shows the time
electronically by means of the liquid held in a thin layer between two
transparent plates.
Lugs: Projection on the watch face to which the watch
band/bracelet is attached.
Main Plate: Base plate on which all the other parts of a
watch movement are mounted.
Mainspring: The driving spring of a watch or clock,
contained in the barrel.
Manual Wind: A manual wind watch must be wound every day by
the crown in order to run. Even with that inconvenience, they are still
produced by the major houses in Switzerland. Some of the most beautiful pieces
made today are manual wind, and you actually won't fund many value or budget
manual winds (but they exist!). With exhibition backs becoming very common,
it's nice to view the active movement without a rotor in the way.
Marine Chronometer: Highly accurate mechanical or electronic
timekeeper enclosed in a box (hence the term box chronometer), used for
determining the longitude on board ship. Marine chronometers with mechanical
movements are mounted on gimbals so that they remain in the horizontal position
is necessary for their precision.
Measurement Conversion: A feature, usually consisting of a graduated
scale on the watch's bezel, that lets the wearer translate one type of
measurement into another -- miles into kilometers, for instance, or pounds into
kilograms.
Mechanical Movement: A movement based on a mainspring which is wound
by hand; when wound, it slowly unwinds the spring in an even motion. An
automatic mechanical requires no winding because of the rotor, which winds the
mainspring every time you move your wrist.
Military or 24-hour
time: When time is measured in
24-hour segments. To convert 12-hour time into 24-hour, simple add 12 to any
p.m. time. To convert 24-hour time into 12-hour time, subtract 12 from any time
13 to 24.
Moon-phase: A window in a watch face that shows which phase
the moon is.
Mother-of-Pearl: 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: The inner mechanism of watch that keeps time and
moves the watch's hand, calendar, etc. Movements are either mechanical or
quartz.
Perpetual Calendar: A calendar that automatically adjusts for the
months' varying length and for leap year. Perpetual calendars, which can be
powered by quartz or mechanical movements, are programmed to be accurate until
the year 2100. Many watch collectors suggest storing mechanical versions in
motorized winding boxes when they aren't being worn in order to maintain the
calendar countdown.
Power Reserve: The amount of energy reserve stored up to keep a
watch running until it stops. The remaining power is sometimes indicated by a
small gauge on the dial.
Power Reserve Indicator: A feature of a mechanical watch that shows how
much longer the watch will operate before it must be wound again.
Push-piece: Button that is pressed to work a mechanism. (The
push-pieces on chronographs, striking watches, alarms, etc.)
Quartz Crystal: A tiny piece of synthetic quartz that oscillates
at the rate of 32.768 times a second, dividing time into equal segments.
Quartz Movement: A movement which allows a watch to keep time
without being wound. This technology employs the vibrations of a tiny crystal
to maintain timing accuracy. The power comes from a battery that must be
replaced about every 1.5 years. In recent years, new quartz technology enables
the watch to recharge itself without battery replacement. This power is
generated via body motion similar to an automatic mechanical watch, or powered
by light through a solar cell, or even by body heat. A digital quartz watch has
no mechanical parts. Most quartz movements are made in Hong Kong, Japan or
Switzerland.
Repeater: A device that chimes the time when the wearer
pushes a button.
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: The part of an automatic watch that winds the
the movement's main spring.
Sapphire Crystal: A crystal (the cover that protects the watch
face) made of synthetic sapphire, a transparent shatter-resistant,
scratch-resistant substance.
Screw-Lock Crown: A crown that can be screwed into the case to
make the watch watertight.
Second Time-Zone
Indicator: An additional dial that
can be set to the time in another time zone. It lets the wearer keep track of
local time and the time in another country simultaneously.
Shock Absorber: Resilient bearing which, in a watch, is intended
to take up the shocks received by the balance staff and thus protects its
delicate pivots from damage.
Shock Resistance: As defined by the US Government regulation, a
watch's ability to withstand an impact equal to that of being dropped onto wood
floor from a height of 3 feet.
Skeleton Case: A case with a transparent front or back that
allows the wearer to view the watch's movement.
Solar Compass: A compass that lets the wearer determine the
geographical poles by means of a rotating bezel. The wearer places the watch so
that the hour hand faces the sun. He then takes half the distance between the
position and 12 o'clock, and turns the bezel until its "south" marker
is at that halfway point. Some quartz watches have solar compasses that show directions
on an LCD display.
Split Seconds Hand: Actually two hands, one a flyback hand the other
a regular chronograph hand. When the wearer starts the chronograph, both hands
move together. To time laps or different finishing times, the wearer can stop
the flyback hand independently while the regular chronograph hand keeps moving,
in effect "splitting" the hand(s) in two.
Stepping Motor: The part of a quartz movement that moves the
gear train, which in turn moves the watch's hands.
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". 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.
Swiss Made: A watch is considered Swiss if its movement was
assembled, started, adjusted and controlled by the manufacturer in Switzerland.
Swiss A.O.S.C.
(Certificate of Origin): A mark identifying a
watch that is assembled in Switzerland with components of Swiss origin.
Sweep Seconds-Hand: A seconds-hand that is mounted in the center of
the watch dial.
Tachymeter: A device on the chronograph watch that measure
the speed at which the wearer has traveled over a measured distance.
Tank Watch: A rectangular watch designed by Louis Cartier.
The bars along the sides of the watch were inspired by the tracks of tanks used
in World War I.
Telemeter: A telemeter determines the distance of an object
from the observer by measuring how long it takes sound to travel that distance.
Like a tachymeter, it consists of a stopwatch, or chronograph, and a special
scale, usually on the outermost edge of the watch face.
30-Minute Recorder (or
register): A subdial on a
chronograph that can time periods of up to 30 minutes.
Timer: Instrument used for registering intervals of
time (durations, brief times), without any indication of the time of day.
Tonneau Watch: A watch shaped like a barrel, with two convex
sides.
Totalizer: A mechanism that keeps track of elapsed time and
display it, usually on a sub-dial.
Tourbillon: A device in a mechanical watch that eliminates
timekeeping errors cause by the slight difference in the rates at which a watch
runs in the horizontal and vertical positions. The tourbillon consist of round
carriage, or cage, holding the escapement and the balance. It rotates
continuously at the rate of once per minute.
Tritium: An isotope of hydrogen that is used to activate
the luminous dots or indices on a watch dial. The radioactivity released in
this process is too slight to pose a health risk.
Uni-directional Rotating
Bezel: An elapsed time rotating
bezel, often found on divers' watches, that moves only in a counterclockwise
direction. It is designed to prevent a diver who has unwittingly knocked the
bezel off its original position from overestimating his remaining air supply.
Because the bezel moves in only one direction, the diver can error only on the
side of safety when timing his dive. Many divers' watches are ratcheted, so
that they lock into place for greater safety.
Vibration: Movement of a pendulum or other oscillating
element, limited by two consecutive extreme positions. The balance of a
mechanical watch generally makes five or six vibrations per second (i.e. 18,000
or 21,600 per hour), but that of a high-frequency watch may make seven, eight
or even ten vibrations per second (i.e. 25,200, 28,800 or 36, 000 per hour).
Water Resistance: A water resistant watch can handle light
moisture, such as a rain or sink splashes, but should not be worn swimming or
diving. If the watch can be submerged in water, it must state at what depth it
maintains water resistance, i.e. 50 meters or more on most sport watches. Below
200 meters, the watch may be used for skin diving and even scuba diving
depending upon the indicated depths.
Winding: Operation consisting in tightening the
mainspring of a watch. This can be done by hand (by means of the crown) or
automatically (by means of a rotor, which is caused to swing by the movements
of the wearer's arm).
Winding Stem: The button on the right side of the watch case
used to wind the mainspring. Also called a "crown".
World Time Dial: A dial, usually on the outer edge of the watch
face, that tells the time 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 wearer
reads the hour in a particular time zone by looking at the scale next to the
city that the hour hand is pointing to. The minutes are read as normal. Watches
with this feature are called "world timers".
Yacht Timer: A countdown timer that sounds warning signals
during the countdown to a boat race.
