|Internet media type|
|Uniform Type Identifier (UTI)||com.microsoft.word.doc|
(19 November 2019)
|Type of format||document file format|
|Container for||Text, Image,Table|
|Extended from||Compound File Binary Format (since 97)|
|Extended to||Microsoft Office XML formats, Office Open XML|
In computing, DOC or doc (an abbreviation of "document") is a filename extension for word processing documents, most commonly in the proprietary Microsoft Word Binary File Format. Historically, the extension was used for documentation in plain text, 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 1983, Microsoft chose to use the DOC extension for their proprietary Microsoft Word format. These uses for the extension have largely disappeared from the PC world.
Binary DOC files often contain more text formatting information (as well as scripts and undo information) than some other document file formats like Rich Text Format and Hypertext Markup Language, but are usually less widely compatible.
The DOC files created with Microsoft Word versions differ. Microsoft Word versions before Word 97 ("8.0") used a different format from the OLE/CFBF-based Microsoft Word 97 - 2003.
The DOC format is native to Microsoft Word. Other word processors, such as OpenOffice.org Writer, IBM Lotus Symphony, Apple Pages and AbiWord, can also create and read DOC files, although with some limitations. Command line programs for Unix-like operating systems that can convert files from the DOC format to plain text or other standard formats include the wv library, which itself is used directly by AbiWord.
Because the DOC file format was a closed specification for many years, inconsistent handling of the format persists and may cause some loss of formatting information when handling the same file with multiple word processing programs. Some specifications for Microsoft Office 97 binary file formats were published in 1997 under a restrictive license, but these specifications were removed from online download in 1999. Specifications of later versions of Microsoft Office binary file formats were not publicly available. The DOC format specification was available from Microsoft on request since 2006 under restrictive RAND-Z terms until February 2008. Sun Microsystems and OpenOffice.org reverse engineered the file format. On February 15, 2008, Microsoft released a .DOC format specification under the Microsoft Open Specification Promise. However, this specification does not describe all of the features used by DOC format and reverse engineered work remains necessary. Since 2008 the specification has been updated several times; the latest change was made in November 2019.
The format used in earlier, pre-97 ("1.0" 1989 through "7.0" 1995) versions of Word are less known, but both OpenOffice and LibreOffice contains open-source code for reading these formats. The format is probably related to the "Stream" format found in similar Excel versions. Word 95 also seems to have an OLE-wrapped form.
Some historical documentations may use the DOC filename extension for plain-text file format. The DOC filename extension was also used in historical versions of WordPerfect for its proprietary format.
Some software applications use the name DOC in combination with other words (such as the name of software manufacturer) for different file formats. As an example, on the Palm OS, DOC is shorthand for PalmDoc, a completely unrelated format (commonly using PDB filename extension) used to encode text files such as ebooks.