(
DOCument file) The default file format in a version of Word, Microsoft's word processing application prior to Microsoft Office 2007. DOC files use a .DOC extension and differ from text files (.TXT extension) because they contain proprietary format codes that must be opened in Word or software that reads the Word format.
DOCX File
Starting with Word 2007, the default Word format is DOCX; however, all versions of Word and most applications that support Word read and write both DOC and DOCX files (see
Office Open XML).
De Facto Standards
Microsoft Word has been used billions of times by Windows and Mac users, and the DOC/DOCX formats are de facto standards for text documents. Contrast with
ASCII file. See
Microsoft Word and
PDF.