Definition: Office Open XML

An XML-based file format developed by Microsoft and standardized by ECMA. Starting with Microsoft Office 2007, Office Open XML is the default document format for saving applications. See Office file formats and ECMA.

A Package of Folders and Files
An Office Open XML (OOXML) document is a zipped (compressed) collection of folders, subfolders, XML files and other file types, which is a huge contrast from previous Microsoft Office and traditional business file formats. One advantage of the Office Open XML structure is that various parts of the document can be edited more easily because they reside in separate files. For comparison, following are the file structures for Word in both the traditional and Open XML formats. See ZIP file.

 #1 - ORIGINAL WORD DOCUMENT (.DOC)
      (Word 2003 and prior)

      resume.doc (one file)


 #2 - OFFICE OPEN XML DOCUMENT (.DOCX)
      (starting with Word 2007)

      resume.docx (one zipped file containing
                   all of the following:)

     _rels FOLDER
     .rels (RELationshipS; pointers to
             app, core and document files)

     docProps FOLDER
     app.xml (page characteristics)
     core.xml (authorship, versions)

     word FOLDER
     document.xml (text content)
     fontTable.xml (fonts)
     settings.xml (spelling, grammar, etc.)
     styles.xml (paragraph styles)
     webSettings.xml (browser attributes)

         _rels SUBFOLDER
         document.xml.rels (pointers to
                            other files)
         media SUBFOLDER
         image1.jpeg (embedded image)

         theme SUBFOLDER
         theme1.xml (foreign language
                       attributes)