A world clock, often called a "Worldtime Clock", is a clock which displays the time for many (or all)places around the world.
The display can take various forms:
- The clock face can incorporate multiple round analogue clocks with moving hands or multiple digital clocks with numeric readouts, with each clock beeing labelled with the name of a major city or time zone in the world.
- It could also be a picture map of the world with inbedded analog or digital time-displays.
- A moving circular map of the world, rotating inside a stationary 24 hour dial ring is another possibility (Or the disc can be stationary and the ring moving)
- Light projection onto a map representing daytime is another option, used in the Geochron, a brand of a particular form or world clock.
There are also worldtime watches, both wrist watches and pocket watches. Sometime manufacturers of timekeepers erroneously apply the worldtime label to instruments that merely indicate time for two or a few timezones, but the term should be used only for timepieces that indicate time for all major timezones of the globe.