.doc

Definition
.doc (an abbreviation of document) is a file extension for word processing documents; most commonly for Microsoft Word.

History
The extension was used for documentation in plain-text format, particularly of programs or computer hardware, on a wide range of operating systems. During the 1980s, WordPerfect used .doc as the extension of their proprietary format. Later, in the 1990s, Microsoft chose to use the .doc extension for their proprietary Microsoft Word word processing formats. The original uses for the extension have largely disappeared from the PC world.