Glossary of Watch Terms
Alarm – Sounds a signal at a pre-set time.
Altimeter – Tells altitude by responding to changes in barometric pressure.
Analog Display – A display that shows the time using hands.
Analog Watch – A watch with a dial, hands, and numbers or markers for telling time.
AR – Anti-reflective coating put on the crystal, sometimes gives off a blue hue.
Automatic Movement – A movement were winding occurs from a rotor through motion that keeps the watch operating, opposed to manual wind or battery (quartz).
Balance Spring – A spring in a mechanical watch that returns the balance wheel back to a neutral position.
Balance Wheel – The part of a mechanical watch that oscillates.
Barrel – box containing the mainspring of a watch.
Beats – Measured by beats per second then generally translated to beats per hour or BPH. Example: 8 beats per second is 28,800 beats per hour.
Bezel – A rotating or fixed ring that goes around the outside of the crystal.
Bidirectional Bezel – A bezel that can be moved either clockwise or counterclockwise.
Bracelet – A watch band made steel, titanium, ceramic, or a precious metal.
Bridge – Fixed to the main plate to form the frame of a watch movement.
Caliber – Used in reference to describe the type/model of movement being used in a watch
Case – The metal housing of a watch’s parts.
Chronograph – Generally acts as a stopwatch, can be started and stopped to time an event utilizing subdials on the watch face.
Chronometer – Certified that it meets C.O.S.C. specifications by running the movements through a series of test and positions.
Complication – Anything besides the standard time functions (hour, minute, seconds). A day and date function would be two complications.
C.O.S.C. – The Official Swiss Chronometer Testing Institute (Contrôle Officiel Suisse des Chronomètres) test movements and certifies that it falls within chronometer standards, generally -4/+6 seconds per day.
Countdown Timer – Counts time down from from a predetermined time. Example, if set for 60 minutes, it will count down to zero. Keeps track of elapsed time.
Crown – Either a pull out or screw down pusher attached to the stem used to change time, day, date, and can be used to wind an automatic or mechanical watch.
Crown Guard – Are on either side of crown, usually found on dive watches to prevent damage to the crown during diving.
Crystal – What you view the watches dial through, often mineral or sapphire crystal.
Day/Date – A watch that indicates the week day and the date.
Deployant Buckle – A type of buckle that open and fastens using hinged extenders.
Dial – The watch face that is visible for viewing time or other complications.
Digital watch – A watch that displays time digitally, opposed to hands (analog).
Dual Timer – A watch that measures current local time and another time zone. This could also be a GMT complication.
Escapement – Device in a mechanical watch that controls the rotation of the wheels .
ETA – Owned by the Swatch Group and are a leading player of Swiss based movements.
Face – The visible side of the watch where the dial is contained.
Gasket – Gaskets used to seal the inside of the watch to help protect against dust, moisture, water, etc.
Guilloche – A type of engraving where very precise intricate designs are are etched. On watches this is most commonly found on the dial or different aspects of the movement.
Horology – The science of time measurement, including designing and constructing the timepieces.
Integrated Bracelet – A watch bracelet that is integrated into the design of the case.
Jewels – Synthetic sapphire or rubies that act as bearings for gears in mechanical watch to reduce friction.
LE – Limited Editions – A watch that produced in specified amount and not made again after the initial run.
Lugs – Come off of the case and is where the bracelet or strap is connected.
Mainspring – This is the spring that “tightens” up to create the power reserve and power the watch.
Manual Wind – A manual wind watch can only be wound by hand, creating the power reserve.
Mechanical – A movement that is hand wound tightening the mainspring.
Moon-phase – A window in a watch face that shows which phase the moon is.
Movement – Movements are often manual, automatic, or quartz. Responsible for keeping time and any complications.
Perpetual Calendar – A calendar that automatically adjusts to the length of the month, including leap years.
Power Reserve – The amount of power reserved to keep the watch running. If a watch is fully wound with a power reserve of 40 hours and set down in will stop in roughly 40 hours later. For an automatic as long as it is in motion before the power reserve runs out it will gain power through the tightening of the mainspring and keep going.
Power Reserve Indicator – Indicates how much power is left before it stops running, usually an automatic or manual movement.
Pushers – Button(s) that are pressed to work a mechanism, usually on a chronograph function.
Quartz Movements – A battery operated watch, which will require replacement unlike a mechanical watch. Its power is constant until it dies.
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 through motion.
Sapphire Crystal – Synthetic sapphire, highly scratch-resistant unlike mineral crystal.
Screw Down Crown – Crown that is screwed into a threaded barrel that aids the water resistance of a watch.
Second Time Zone – Simply a complication that can be set to a different time zone on the dial.
Shock Resistance – Based on the simulation of the shock received by a watch falling from the height of 3 feet onto a horizontal hardwood surface, issued by the International Organization for Standardization.
Skeleton Case – Allows visualization of a movement through the face or back of the watch.
Slide Rule – Scale on the outer edge of the watch face that integrates usually with a bidirectional bezel which enables the ability to do mathematical calculations.
Swiss Made – According to Swiss law, a Swiss-made watch means that at least 50% of the parts are Swiss made and that the assembly, finishing, and final inspection occurs in Switzerland.
Sweep Seconds-Hand – A seconds-hand that is mounted in the center of the watch dial.
Tachymeter – A measuring system on the outer bezel that is used to measure speed.
Titanium – 30% stronger and about 50% lighter than steel, also hypoallergenic.
Tourbillon – Consist of a round carriage, or cage, holding the escapement and the balance wheel. This is the pinnacle in watch making and is highly coveted for the knowledge and craftsmanship it takes build. It is common place for these watches to be in excess of 100K USD.
Tritium – An isotope of hydrogen that is used to activate the luminous dots or indices on a watch dial.
Two Tone – Two different metals being used on watch, like gold and stainless steel.
Unidirectional Bezel – Only moves counterclockwise.
Vibration – Measured by vibrations per second then generally translated to vibrations per hour or VPH. Example: 8 beats per second is 28,800 vibrations per hour.
Water Resistance – No watch is technically water proof! If a watch states only “water resistant” then it can only handle small amounts of moisture, do not submerge. If the watch states for example “water resistant 200m”, it is good for swimming or diving.
Winding – This tightens the mainspring of a watch either with a rotor on automatic or the crown on manual wind movements. This can also be done with the crown on automatic movements, but not a necessity.