Filename extension

A filename extension is an identifier specified as a suffix to the filename of a computer file.

Description

The extension indicates a characteristic of the file contents or its intended use.

A file extension is typically delimited from the filename with a full stop (period).

Some file systems implement filename extensions as a feature of the file system itself, and may limit the length and format of the extension, while others treat filename extensions as part of the filename without special distinction.

See also

• Computer file
• Filename
• Identifier
• List of file formats
• List of filename extensions
• Metadata
• Windows file types

External links

• Filename extension @ Wikipedia