Glossary
While most "Paneristi" understand what horlogerie terms mean, many laypeople do not. Below is a glossary of terms along with definitions.
AISI 316L: a type of stainless steel that is often used in stainless steel watches due to its high resistance to corrosion. This is the type used by Panerai.
Automatic: a movement that winds the mainspring by moving the arm (human), which causes a rotor to wind the mainspring through specific gears.
Balance: a circular moving part that oscillates on an axis. It works in conjunction with the balance spring to divide time into equal parts. The more the balance oscillates, the higher the frequency and accuracy.
Balance spring: the elastic component that allows the balance to make regular oscillations. It is also the piece that regulates the watch. It can be shortened to increase speed or lengthened to slow down.
Barrel: cylindrical box that contains the mainspring. While the mainspring is wound by the arbor (or axle), it is powered by the barrel that rotates slowly (usually one rotation every 8 hours). The mainspring is coiled around the arbor and unravels following the rotation of the barrel. In a hand-wound movement, a 40 hour spring will unwind in 5 barrel rotations, at which point the movement will stop.
Bezel: ring around the case that secures the crystal. A rotating bezel is used to calculate duration. Dive watches have uni-directional bezels for safety; if the bezel moves accidentally, then dive duration will be shortened rather than lengthened.
Black Seal: Italian special operations divers. In their black rubber dive suits they looked like black seals.
Calibre: designates the watch movement. The casing diameter is measured in lignes, or more recently in millimetres.
Case: part of the watch that encloses the mechanism/movement.
COSC: Controle officiel suisse des chronometres. This certification awards the title of "Chronometer" if a watch has demonstrated 15 days of accuracy at a COSC official bureau. The watch is tested at five positions and various temperatures. COSC certification is given to individual watches, not a model or type.
Crown: button that is used to wind the watch.
Crystal: transparent cover that protects the watch face. Higher end watchmakers, such as Panerai, use sapphire due to its exceptional hardness and resistance to scratches.
Dial: the face of the watch that displays the time.
ETA: ETA SA Manufacture Horlogere Suisse produces mechanical and quartz movements for many different watchmakers. It is owned by The Swatch Group.
Flyback: function that was devised initially for pilots who needed to make quick chronograph calculations on the fly. The flyback allows for the chronograph hand to be reset to zero and restarted again by pressing the push piece only once. A regular chronograph would require four pushes (start, stop, reset, start).
Frequency: the number of oscillations each second, which is measured in Hertz. The balance goes back and forth at a given frequency. In essence, the higher the frequency, the more accurate the watch is.
GMT: Greenwitch Mean Time.
Jewels: rubies (type of corundum) or synthetic rubies are used to make bearings (jewels) for a watch's various moving parts. Rubies are ideally suited for this because they are very hard, thus reducing friction and wear. Watchmakers will place jewels where there is the most friction, such as components that frequently touch others through movement. A basic mechanical watch that displays hours, minutes and seconds should have a minimum of 15 jewels.
Ligne: the old standard of measurement in watchmaking. One ligne is equal to 2.2558mm or rounded to 2.26mm.
Manual: a movement that is wound by hand by turning the winding crown.
Movement: the internal mechanism of a watch.
OP: the OP logo not only represents "Oficine Panerai", but the two arrows pointing up and down are references to the fact that Panerai makes products for both underwater and aerial uses.
Oscillation: the movement of the balance between two extreme points. The movement from one point to the other is equal to one oscillation. One oscillation is equal to two vibrations (or alternations). If a balance produces 9,000 oscillations per hour, then it is equivalent to 18,000 vibrations per hour.
PAM: PAnerai Model = PAM.
Pre-vendome: the era of Panerai's revival between 1993 and the 1998 Richement acquisition.
Rattrapante: a type of chronograph that has two seconds hands. Both hands can be started together with one push. The second push will stop one hand while the other continues, and a third push will restart the stopped hand in order to catch up to the other. A rattrapante is useful for measuring time intervals.
Sealand for Purdey: watches made in cooperation with Purdey (gun manufacturer) that have animal images engraved on the case lid, which flips open to reveal the dial.
Tourbillon: one of the most complicated mechanisms devised. The tourbillon compensates for errors of rate caused by the Earth's gravitational force in upright positions. This increased stability makes a mechanical watch far more accurate.
Valjoux: Swiss manufacturer of mechanical watch movements. Valjoux is also part of ETA, and thus also owned by The Swatch Group. Most mechanical chronograph watches on the market today are powered by the Valjoux 7750 movement.
Wheel: a circular component whose rotational movement transfers power or motion.