Acrylic Crystal: This is a plastic that is used for many of the faces of running watches. Although it is resistent to shattering, it does scratch easily. Typically, you can use some toothpaste to polish out the scratches.
Alarm: A typical function of most watches found on a runner’s wrist is the alarm. You can program it to beep at a specified time.
Battery EOL: Battery End Of Life indicator. Your watch numbers will flash, or a screen warning will indicate when your watch battery is low.
Calendar: Most runners watches have a built in calendar with various calendar and reminder type features. However, the calendar is typically used just to show you the day of the week.
Chronograph: The chronograph is possibly the single most important feature of your watch. Time is measured usually from tenth or hundredth of a second to hours and sometimes days. A typical runners watch will also have a chronograph memory to store your time and a split mechanism.
Crown: In rare instances, a runner’s watch will have a crown. The crown is used in analog watches for winding and setting the time. In a digital watch, it is sometimes used for similar purposes.
Crystal: Typical types of crystal are acrylic, mineral (glass) and sapphire. Essentially, these are used to cover the dial (or face) of the watch.
Dial: The dial is also known as the face of the watch. The numbers show through the dial.
GPS (Geo-Positioning System): This is the technology that allows some running watches to track your position providing reasonable estimations of the distance of your run.
LCD Display (Liquid Crystal Display): The common display mechanism of most watches used by runners.
Luminova: This is the glow-in-the-dark material used by most watches to provide a nightime glow.
Mineral Crystal: Scrath resistant watch crystal that is essentially glass.
O-Ring: The back of the watch which is either pressed-in or screwed on. Provides resistence from water
Quartz: An oscillating quartz watch is known for its accuracy and use in digital watches. The watch battery powers the oscillating quartz crystal to run the display.
Shock-Resist: Watch components that are protected by shock absorbing material are shock resistent.
Water Resistant: Water resistancy in watches is usually measured in meters, meaning they can withstand submersion to the recommended level.