Watch Terminology

Automatic Movement

A mechanical movement that is wound through the motion of the arm during normal daily wear; sufficient activity is required to build up a power reserve. Also know as “self-winding” and "perpetual" motion.



The rim which secures the crystal in place on the watch case. May be set with diamonds, or graduated to track elapsed time, as in a diver’s watch.



Subdials (windows or apertures in the dial) which display the day, month and/or year.



A numeric or alpha-numeric designation for the mechanical or quartz workings of a watch/clock.



A type of stop watch used to record the elapsed time of an event. Watches with a chronograph function are themselves called “chronographs.”



A timepiece that has met very high standards of accuracy, tested and certified by an official watch institute (COSC) in Switzerland. It also comes with an individual certificate of precision.  Chronometer certification indicates that the mechanical watch or clock loses no more than 4 seconds and gaines no more than 6 seconds in the span of a day in specific positions.



The tiny knob on the winding stem used to manipulate the time, and to wind a mechanical watch with a manual movement.



Sometimes refered to as the "face" of a watch, it is the surface marked with numbers or indexes, protected by the watch crystal on which the time is displayed. Also known as the watch “face.”



A type of energy accumulation system for watches comercialized by the Citizen Watch Company.  The concept works by gathering light through a solar-cell just behind the semi-transparent dial of the watch.



A small synthetic ruby placed at various points in the mechanical or quartz movement of a watch to reduce friction where two metal parts would otherwise rub against each other.


Kinetic Watch

A quartz regulated watch that accumulates energy from an internal weight that swings from the wearer's daily activity to charge the capacitor.  Developed and trademarked by the Seiko Watch Company.



Extensions from either end of the case that hold the pin used to fasten the strap or bracelet to the case.


Luminous Hands

Watch hands coated with a substance such as tritium that makes them glow in the dark, especially in sports models for better visibility underwater.


Mechanical Movement

Comprised of a series of turning cog wheels and jewels, expertly calibrated by hand. A mechanical movement may be “automatic,” also known as “self-winding” (wound by the motion of the arm during daily wear) or “manual,” also known as “hand-winding” (requiring regular winding by hand).



A window in a watch face that shows the current phase of the moon.


Power Reserve Indicator

An aperture or subdial on mechanical watches that shows how much longer the watch will operate before requiring winding.


PVD Coating

A high tech vacuum-coating procedure that produces a very scratch- and wear-resistant finish. Similar but superior to ion-plating, because the applied layer is generally thicker, with a higher material density. In quality, PVD (the letters stand for “physical vapor deposit”) coatings compare to gold-plating to a thickness of 10 microns.


Quartz Movement

A watch movement where time is “tuned” to, and measured by, the extremely rapid and consistent vibrations of a quartz crystal. Also known as “electronic quartz movement.”



A device that chimes the time when a button is pushed or a slide is pulled.


Skeleton Case

A transparent front or back which allows the watch’s movement to be viewed.


Screw-Down Crown

A crown that can be screwed into the case increasing the water resistance of a watch. Provides the best underwater shock protection (against rocks, accidental knocks, scrapes, etc.) to prevent water leakage.


Self-Powered Quartz Movement

A battery-free movement that offers quartz accuracy. Mechanical energy generated by the force of gravity and natural movements of the wearer’s wrist is converted into electrical energy which powers the watch.


SKU Number

An identifying number used when taking inventory, short for “stock keeping unit.” Same as the watch model number.

Sweep Seconds Hand

A second hand that is mounted on the center of the watch dial (vs. one in the sub-dial). The motion of the “true” sweep seconds hand is undetectable to the human eye, and found only on mechanical watches. On a quartz watch, the advance of the seconds hand is discernable in tiny step-by-step jumps.



A feature found on chronographs which measures the wearer’s speed of travel over a pre-determined distance.


Technical Reference Number

A number (used in addition to the SKU number) that provides coded information on the watch’s attributes: case metal, plating, movement size and type, bracelet style, dial color, material, and style. It is usually engraved into the case back.



A construction system in a mechanical watch that eliminates timekeeping errors caused by the slight difference in rates at which a watch runs in the horizontal and vertical positions. A rare and sophisticated feature.


Water Resistance

The ability of a watch to withstand water pressure to a stated depth. Tested to meet international standards, water-resistant watches may be worn while swimming or snorkeling.