Glossary of Watch Terms.

sapphire crystal: A crystal made of synthetic sapphire, a transparent, shatter-resistant, scratch-resistant substance.

screw-lock crown: A crown that can be screwed into the case to make the watch watertight.

second time-zone indicator: An additional dial that can be set to the time in another time zone. It lets the wearer keep track of local time and the time in another country simultaneously.

shock resistance: As defined by U.S. government regulation, a watch's ability to withstand an impact equal to that of being dropped onto a wood floor from a height of 3 feet.

slide rule: A device, consisting of logarithmic or other scales on the outer edge of the watch face, that can be used to do mathematical calculations. One of the scales is marked on a rotating bezel, which can be slid against the stationary scale to make the calculations. Some watches have slide rules that allow specific calculations, such as for fuel consumption by an airplane or fuel weight.

solar powered: A watch that uses solar energy (from any light source) to power the quartz movement. The Citizen >Solar-Tech stepping motor: The part of a quartz movement that moves the gear train, which in turn moves the watch's hands.

stopwatch: A watch with a seconds hand that measures intervals of time. When a stopwatch is incorporated into a standard watch, both the stopwatch function and the timepiece are referred to as a chronograph.

sub-dial: A small dial on a watch face used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date.