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 Right, 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.
Amplitude: Maximum angle by which a balance swings from its position of rest.
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
Arbor: This is any post or axle that a moving part swings or rotates upon. Picture a gear with a post running through the center. That post/axle is called an "Arbor".
Assembling: The process of putting together a watch. The assembly and manufacture of parts was formerly done entirely by hand but today are done by machine with inspection and timing for accuracy done by hand.
Automatic Watch: 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.
Balance Cock: A small bridge that secures the balance wheel with the movement.
Balance Spring: An extremely fine coil like spring that swings the balance back and forth in a mechanical watch and is as thins as a hair.
Balance Staff: Shaft or "arbor" upon which the balance swings back and forth. This is the "heart" of a watch.
Balance Wheel: The part of a mechanical watch movement that oscillates, dividing time into equal segments: much like that of the pendulum in a clock.
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 plating, or steel) that surrounds the watch face.
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.
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.
Chronograph: A complicated watch that has separate functions and dials. Usually for timing. The first chronographs were designed for complicated calculations required by pilots and aviators.
Chronometer: A timepiece that has met certain high standards of accuracy set by the Controle Officiel Suisse des Chronometeres in Switzerland.
Complicated Watch: A 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.
Crystal: Plastic, glass, or sometimes sapphire cover that allows the dial to be viewed without opening the watch-case
Cuvette: Inner dust cover on a watch case.
Dial: Face of a watch with hour indicators.
Dimaskeening: Fancy decorative etching on some watch movements.
Dual Timer/Dual time zone watch: As the name indicates, this watch tells time in two locations around the globe.
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.
Elapsed Time Rotating Bezel: Used on many dive watches and chronographs, this is a bezel with minute markers. The bezel can be turned to align an arrow (zero) with the minute hand. Time elapsed can then be tracked. Example: After ten minutes have elapsed, the minute hand will point at the "10" marker on the bezel.
Elinvar: A hairspring made from a specific mix of metals that is resistant to changes in temperature, therefore, more accurate in different situations (including hot and cold). Derived from the term Elasticity Invariable.
End Shake: When a jewel hole is worn allowing an arbor to "shake"
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: See Dial.
Fob: Watch Chain.
Fork: Part of the Pallet-Fork and Arbor. The fork engages the roller jewel on the balance, and resembles a small pitch-fork
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"
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.
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)
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.
Jewels: A bearing made of ruby or synthetic sapphires that act as bearings for gears in a mechanical watch, reducing friction and wear.
Jump Hour: A watch that uses two dials instead of hands to shows the hour and minutes by means of a numeric window on the watch face.
Key Set: Watch that is set by means of a small key instead of by a crown. Earlier watches were key-set.
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.
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.
Micrometric Regulator: Regulator that is finely tuned by the adjustment of a small screw. Used in high grade watches.
Moon-phase: A window in a watch face that shows the current phase of the moon.
Movement: The inner mechanism of a watch that keeps time and moves the watch's hands calendar, etc. Movements are either mechanical or quartz.
Oil Sink: Recessed well around a pivot on a bridge that holds a small amount of oil to lubricate the motion of the arbor/gear.
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.
Power Reserve Indicator: A feature of a mechanical watch that shows how much longer the watch will operate before it must be wound again.
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.
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.
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.
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.
Winding Stem: The stem is an internal part of the watch to which the crown is attached.