What is a time zone?

In a nutshell

A time zone is a geographical area (typically a collection of countries) that observes the same standard time. Time zones help make it easier for people living within an area to coordinate their activities according to the same time.

Time zones are usually defined as offsets from Universal Coordinated Time (e.g., UTC-4 or UTC+8).

See this interactive map to explore the different time zones in the world.