[16][17][better source needed] At the time of its first release, the name "Vim" was an acronym for "Vi IMitation", but this changed to "'Vi IMproved" late in 1993.

Depending on the mode, typed characters are interpreted either as sequences of commands or are inserted as text.

In Vim there are 14 editing modes, 7 basic modes and 7 variants:[37] Vim is highly customizable and extensible, making it an attractive tool for users who demand a large amount of control and flexibility over their text editing environment.

The "recording" feature allows for the creation of macros to automate sequences of keystrokes and call internal or user-defined functions and mappings.

Abbreviations, similar to macros and key mappings, facilitate the expansion of short strings of text into longer ones and can also be used to correct mistakes.

There are projects bundling together complex scripts and customizations and aimed at turning Vim into a tool for a specific task or adding a major flavour to its behaviour.

Examples include Cream, which makes Vim behave like a click-and-type editor, or VimOutliner, which provides a comfortable outliner for users of Unix-like systems.

[44] Some of Vim's enhancements include completion functions, comparison and merging of files (known as vimdiff), a comprehensive integrated help system, extended regular expressions, scripting languages (both native and through alternative scripting interpreters such as Perl, Python, Ruby, Tcl, etc.)

including support for plugins, a graphical user interface (gvim), limited integrated development environment-like features, mouse interaction (both with and without the GUI), folding, editing of compressed or archived files in gzip, bzip2, zip, and tar format and files over network protocols such as SSH, FTP, and HTTP, session state preservation, spell checking, split (horizontal and vertical) and tabbed windows, Unicode and other multi-language support, syntax highlighting, trans-session command, search and cursor position histories, multiple level and branching undo/redo history which can persist across editing sessions, and visual mode.

[citation needed] While running, Vim saves the user's changes in a swap file with the ".swp" extension.

Since version 7, Vim script also supports more advanced data types such as lists and dictionaries and a simple form of object-oriented programming.

Vim script files are stored as plain text, similarly to other code, and the filename extension is usually .vim.

While vi was originally available only on Unix operating systems, Vim has been ported to many operating systems including AmigaOS (the initial target platform), Atari MiNT, BeOS, DOS, Windows starting from Windows NT 3.1, OS/2, OS/390, MorphOS, OpenVMS, QNX, RISC OS, Linux, BSD, and Classic Mac OS.