file type definition file format
The kind of data stored in a file. Most modern operating systems
use the filename extension
to determine the file type though others store this information elsewhere in the file system
. The file type is used to choose an appropriate icon to represent the file in a GUI
and the correct application
with which to view, edit, run, or print the file.
Different operating systems support different sets of file types though most agree on a large common set and allow arbitrary new types to be defined.
See also MIME
FileInfo.com - The File Extensions Resource (http://fileinfo.com/)