A ZIP file is a so-called archive file in which one or more files can be archived and packed.
Since the ZIP format developed in container format in 1989 and the pack algorithms used are free of charge, it quickly became popular and is still one of the most popular pack formats today. The ZIP format has of course evolved since its introduction and also supports encryption (AES up to 256bit) and distribution to multiple files.
On all important systems there are several applications that can unzip and create ZIP archives. Since XP, Zip archives are supported directly and the content is displayed in the Explorer window. Windows users can easily create Zip archives by right-clicking on a file or folder selection and choosing Send To -> Zip Compressed Folder. Mac OSX users can accomplish this in the same way via the menu item "compress [file name]".
In addition, there are a number of free and commercial pack programs whose functionality goes far beyond just unpacking and creating Zip archives. However, be careful with the file extension, in addition to ZIP there
For example, it is still bzip or gzip. These are not compatible and can not be unpacked with the simple ZIP implementations of Windows or Mac OSX.
The Zip format captivates above all by its spreading, fast archiving and a neat packing rate.
However, competing formats such as Rar or 7zip, which are now also very popular, especially on the Internet, often have a much higher compression rate at similar processing speeds.
In addition to being used as a pure archival format, ZIP is also sometimes used by some games (e.g., Battlefield2, Empire Earth 2, Falcon 4) and application programs as a quasi-data format (e.g., Stardock ObjectBar). Here are the actual (game) data as a zip, but can be used directly by the application or the game.
Of course, these ZIP files are not to be considered compatible, as the data contained therein can only be used by the respective program. In some cases, the files are otherwise encrypted so that they can not be unzipped with a standard ZIP program