An annual calendar is a complication which displays the date with minimal correction. The complication tracks the number of days in each month advancing from 30 to 1 on months with only 30 days and from 31 to 1 on moths with 31 days. The calendar requires correction only on March 1^st.

Mechanical watches that are automatic or self-winding rely on the natural motion of the wearer to keep the watch wound. The watch mechanism has an eccentric oscillating weight that turns when the person wearing the watch moves their wrist. The movement of the oscillating weight keeps the mainspring wound.  If the watch is not worn for a period, you may turn and/or wind the crown a dozen or so times to start the watch.

A Big-Date mechanism indicates the date using 2 independent discs, one for the units and one for the tens, which allow the numbers to display larger than they could with a single disc with 31 numbers.

The external component in which are contained all the other parts of the watch including the movement, dial, hands, etc. Usually a crystal and case back are fit to the case to provide protection while allowing the wearer to view the time.

An individual who has successfully demonstrated to a professional certifying body his/her capability to perform clock repairs to a specific standard. The American Watchmakers-Clockmakers Institute is the only independent body certifying clockmakers in the United States.

A CC21 is a clockmaker who has successfully completed the 10 part exam demonstrating their proficiency in servicing mechanical clocks according to standards promoted by the American Watchmakers-Clockmakers Institute.

An individual who has successfully demonstrated to a professional certifying body his/her capability to perform watch repairs to a specific standard. The American Watchmakers-Clockmakers Institute is the only independent body certifying watchmakers in the United States.

A CW21 is a watchmaker who has successfully completed the 3-day exam demonstrating their proficiency in servicing modern timepieces according to standards promoted by the American Watchmakers-Clockmakers Institute and recognized by major manufacturers.

A chronograph is a timepiece capable of recording elapsed time (like a stop-watch) in addition to indicating the time of day. A chronograph usually has several sub-dials with hands to indicate the elapsed seconds, minutes, and sometimes hours of a given event. The chronograph is activated by depressing a button or pusher on the case of the timepiece.

A chronometer is a watch which meets a specific criteria for accuracy and precision in performance.

An individual who makes and/or repairs clocks.

A complication is any mechanism that is part of a watch that indicates any information other than the time of day. Common complications include: date, day of week, phases of the moon, and chronograph. Less common complications include: perpetual calendars, repeating mechanisms, tourbillon, sunrise and sunset indication, sidereal time, and more.

COSC is Contrôle Officiel Suisse des Chronomètres, the Official Swiss Chronometer Testing Institute, which is the institute responsible for certifying the accuracy and precision of wristwatches in Switzerland. COSC certified wristwatches must maintain accurate timekeeping to within -4/+6 seconds per day in various positions and environments.

The crown is a button which protrudes from the case that when turned and can be used to wind a watch or set the time.

A transparent material affixed to the case which protects the dial and hands through which the wearer can observe the time. Usually made from mineral glass, plastic, or sapphire.

A set of components that are part of a watch movement which indicate the number of the date of the given month. The date can be displayed on a rotating disc through a window or by a hand which points to a number on a dial.

A dial is a thin disc with numerals or other indications across which a hand or hands pass to indicate a value. In a watch the dial is usually marked with numerals to represent the hours and/or minutes. Sometimes the dial is called the “face” of the watch.

The hands are thin pieces of metal which rotate over the dial of the watch indicating the time of day.

Horology is the art and science of time measurement. Professionals who make or repair timekeeping devices are called “horologists.”

The jewels in a fine timepiece are bearings or bushings made from gem material (usually synthetic ruby)

The lugs are the protruding portions of the case between which a strap or bracelet is attached.

The US Federal Trade Commission (FTC) requires that products labeled with “Made In The USA,” “US Made,” or other similar labels must be all or virtually all made in the United States or its territories. Additionally all components must make a substantial transformation in the United States. This makes it extremely difficult for any watches to claim to be “Made In the USA.”

A mechanical watch is a timekeeping device that is powered purely my mechanical means, i.e. by a spring or springs as opposed to being powered by electricity.

A complication which displays the date, without any need for correction. The perpetual calendar keeps track of the length of each month including February and even advances correctly on leap years.

A quartz watch is a timekeeping device that is regulated by a quartz crystal which vibrates at a controlled frequency when electrified. Quartz watches require a battery, solar panel, or other means of supplying an electric current.

A quick-set date has a mechanism whereby the date can be quickly advanced by turning the crown without having to rotate the hands around the dial.

See Automatic Watch

A spring bar is a cylinder with two spring loaded tips used to secure a bracelet or strap between the lugs of a watch case.

The stem is a threaded metal linkage which connects the crown on the case to the movement inside the case.

In order for a watch to be labeled as “Swiss Made” it must be assembled in Switzerland and 60% of its manufacturing steps and costs must occur in Switzerland. Compare to Made in the USA.

The tourbillon is a complication developed to improve the timekeeping of pocket watches. In a tourbillon the balance wheel and escapement rotate once per minute in a cage attached to the fourth wheel. The constant rotation averages the effects of gravity on the balance wheel allowing it to be adjusted for better timekeeping.

A watchmaker is an individual who makes or repairs watches. To avoid confusion a company which makes watches is often called a Manufacture where as a watchmaker is an individual who works at a Manufacture or who services or restores timepieces.