A time zone is a region on Earth that has a uniform, legally mandated standard time. It is often represented by an identifier, such as "America/Los_Angeles". Note that a numeric modifier such as "-07:00" is an _offset_. A time zone encodes additional details like Daylight Saving Time.
A time zone is a region on Earth that has a uniform, legally mandated standard time. As legal definitions of zones can vary wildly and change often, a database or lookup table is often required to properly apply time zone rules.
Questions using this tag will usually relate to conversion issues between timezones or conversion bewteen datatypes where one has timezone data encoded and the other does not.
A helpful shareable reference for single timestamp comparisons is https://www.timeanddate.com/worldclock/converter.html
Please see the related tag wiki on StackOverflow for very long-form reading on the matter.