A

alarm: Much the same as an alarm clock, an alarm watch will alert the wearer with beeps at a pre-set time.
analog: A watch that shows the time using hour and minute hands.
automatic winging: See self winding

B

bezel: The metal ring that is around the watch crystal of directly under it. Can be made of gold, gold plate or stainless steel.

calendar: The part of the watch that indicates day of the week and/or month. Can be displayed via a "cut-out" in the dial or through the use of sub-dials.
chronograph: Watch with a built in stop watch style device. There are many different types of chronographs. Some may show elapsed minutes or even hours as well as elapsed seconds. Chronograph & chronometer are not the same thing. The words are not interchangeable.
chronometer: refers to Swiss watches that meet standards set by the Swiss Official Chronometer Control. Due to these standards, chronometers are very high grade watches.
crown: Part of watch that is turned to change the time, date, etc. also used to wind the watch. Sometimes referred to as the stem.
crystal: The transparent cover over a watch dial - usually made of glass, crystal, or plastic.

dial: The "face" of the watch - will have numbers or other markers to denote the hour & minute positions. Watches can also have sub dials - which may indicate seconds or some other special function of that particular watch
digital: Displays the time through numerical digits rather than through a dial and hands.
diver's: A watch that is water resistant to 200M. They have screw-on crowns and backs to increase water tightness. Vintage diver's watches will also have a metal bracelet - not a leather strap.
doctor's: Watch with a separate seconds dial or center seconds dial that is large for easy reading when taking a pulse.

escapement: Controls the rotation of the wheels and movement of the hands in a mechanical movement.

flyback hand: A hand that springs back to zero - used on chronographs to record lapsed time.

GF: Gold filled
gold filled: Watch cases made from layers of gold with brass or other base metal in between.
gold plated: Light layer of gold electronically plated over brass or other type of metal. Not as long lasting as gold filled.

integrated bracelet: A watch band that is incorporated into & part of the design of the case. It is not a separate piece.

LCD: liquid crystal display
liquid-crystal display: Shows the time electronically using a liquid suspended between two transparent layers. LCD watches have quartz movements.
lugs: Extensions on either end of a watch case to which the band or bracelet is attached.

mechanical movement: Vintage watch movements are powered by a mainspring and a balance wheel. Mechanical movements must be wound - either manually or via a self winding mechanism - on a regular basis. They are not battery operated.
movement: The inner mechanisms which control the watch's hands, calendars, sub-dials, alarms, etc.. Movements are either mechanical or quartz.

NOS: New Old Stock - items that remained in stores unsold & in stock. They are as they were shipped from the factory. While MIB (mint in box) items may have been purchased & never used, NOS were never even purchased.

rotor: Part of a self-winding movement which pivots in conjunction with the movement of the wearer's wrist - thus winding the mainspring.

self winding: A watch that is wound by the motion of the wearer's arm instead of by winding the stem. If an self winding watch is not worn for a few days, it will wind down. This type of watch is also referred to as automatic winding
shock resistant: According to U.S. government regulation, a watch must be able to withstand to impact equal to being dropped to a wood floor from a height of 3 feet in order to be labeled shock resistant.
sub-dial: Smaller dial located on the watch face or main dial used for such purposes as displaying seconds or dates. A watch can have no sub-dials or several sub-dials.

tank watch: Commonly used to refer to a rectangular mans watch. Originally used to refer to a specific watch by Cartier which incorporated design elements resembling WWI tank tracks.

water resistant: A watch that is moderately waterproof & will withstand unexpected exposure to water for a very short time (such as splashes). Does not always mean the watch is submersible.