.DOC (Microsof Word document file, .doc)

DOC or doc (an abbreviation of 'document') is a file extension for word processing documents; most commonly for Microsoft Word. Historically, 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.

Proprietary DOC files often contain more text formatting information (as well as scripts and undo information) than files using other document file formats like Rich Text Format and HyperText Markup Language, but are usually less widely compatible.

The DOC format varies among MS Office Word Formats. Word versions up to 97 used a different format than MS Word version between 97 and 2003. With the release of Office 2007, Microsoft uses a new XML-based format with the DOCX extension which is natively supported in Office 2007 and also by older versions of Office if the freely downloadable Compatibility Pack is installed.

The DOC format is native to MS Office Word, but other software, such as OpenOffice, AbiWord and KWord, can create and read .doc files. Due to the closed nature of the .doc file format, high-level formatting (including headers and footers) is often lost when written in one program and opened in the other.

On the Palm OS, DOC is shorthand for PalmDoc, a completely unrelated format used to encode text files such as ebooks.