Here's the glossary of 27 must know watch terms Glossary.(With reference from ProfessionalWatches.com)
Aperture: Small opening in the dial that displays certain information such as date, day, month or moon phase.
Applique: Numerals or symbols cut out and stuck to the dial.
A measurement of pressure called an atmosphere. An atmospheric measure
is the amount of air pressure at sea level that a watch can withstand.
(1ATM = 1BAR = 10m = 33.3ft).
Self-winding watch whose movement is mechanical. A weight (the rotor)
turns by the motion of your arm and winds the mainspring. The energy
generated by the movement is transferred into mechanical energy that
creates the movement. These watches can be shaken or manually wound if
the power reserve runs out.
Bezel: The ring around the top
of the crystal. Generally holds the glass or crystal in place. A
rotating ratchet bezel moves in some watches as part of a complication.
Rotating bezels either rotate clockwise, counterclockwise or both to
assist in calculations.
Caseback: Bottom of the watch that lies against your skin.
Chronograph: Stopwatch function that uses sub dials to keep track of seconds, minutes and hours.
Chronometer: A very precise watch that is tested for 15 days and nights at five different positions and temperature ranges.
Any "function" added to a watch, such as a minute repeater, countdown
timer, stopwatch, altimeter, asthometer, pulsometer, calendar, moon
phase indicator, split second chronograph, power reserve indicator, or
C.O.S.C.: Controle Officiel Suisse des Chronometres
(Official Swiss Chronometer Testing Institute). They test watches for
15 days and nights at five different positions and temperature ranges.
They either pass or fail the watch movement. If the watch passes, it is
called a chronometer.
Crown: Knob used to wind a mechanical watch and to set the time or calendar of a watch.
End of energy: The end of energy in a "mechanical" watch is indicated by the seconds hand, which jumps every two, three or four seconds.
End of life: The end of battery life in a "quartz" watch is indicated by the seconds hand, which jumps every two, three or four seconds.
Most water-resistant watches are equipped with gaskets to seal the
caseback, crystal and crown from water. Gaskets need to be checked every
couple of years to maintain water resistance.
Guilloche: Decoration found on the dials of high-end watches.
Hacking: A feature that stops the second hand when the stem is pulled out as far as it will go. This allows you to set the exact time.
Horology: Science of time measurement, including the art of designing and constructing timepieces.
Isochronism: Equal periods of time. A watch's ability to maintain its rate as the mainspring unwinds.
Ligne: Traditional unit of measurement used to measure the diameter of watch movements.
Luminous paint: Self-illuminating paint that is put on the hands and markers to read the time in low light situations.
Physical Vapor Deposition. Method of coating thin watch cases by
integrating titanium particles and then depositing gold for color
(usually comes in black finish).
Rattrapante: Addition of a second hand to measure split times.
A watch that is accurate to +/- 10 seconds per year. A technology that
uses quartz crystal oscillators working with an integrated circuit,
assuring up to 10 times more accuracy than a conventional quartz watch.
Stopwatch or chronograph function with a scale that measures the
distance of something from the wearer of the watch through the amount of
time it takes sound to travel.
Triple date calendar: Complication that provides month, day and date.
Waterproof: No watch is 100% waterproof.
Analog watch that is able to display functions at the touch of a
button. An easily legible white numeric display appears on the inside
surface of the crystal when any digital function is activated.