The decorative stone set in the watch crown.

The ring surrounding the watch dial and sapphire crystal.

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

A three-folding enclosure which secures the two ends of the bracelet and allows enough room for placing the watch on the wrist when fully deployed. When closed the buckle covers the two-piece folding mechanism.

An indicator that keeps track of the phases of the moon.

A watch with a dial that indicates up to 24 time zones around the world, usually found on the outer edge of the face or sometimes on the bezel.

The main body of the watch containing the watch movement or main components.

A function that provides altitude by responding to changes in barometric pressure, commonly found in pilot watches.

A thin metal rod fixed between the horns, for attaching the wrist band.

The regulating organ of the watch, vibrating on a spiral hairspring. Lengthening or shortening the balance-spring makes the balance-wheel go faster or slower to advance or retard the watch. This is the wheel that is driven by the main spring and that is controlled by the escapement.

One millionth of a second.

Device that converts chemical energy into electricity. Most watch batteries are the silver oxide type delivering 1.5 volts.