Office Open XML (also informally known as OOXML or OpenXML) is a zipped, XML-based file format developed by Microsoft for representing spreadsheets, charts, presentations and word processing documents. The format was initially standardised by Ecma (as ECMA-376) and, in later versions, by ISO and IEC (as ISO/IEC 29500).
Starting with Microsoft Office 2007, the Office Open XML file formats have become the default target file format of Microsoft Office. Microsoft Office 2010 provides read support for ECMA-376, read/write support for ISO/IEC 29500 Transitional, and read support for ISO/IEC 29500 Strict
OPENXML provides a rowset view over an XML document. Because OPENXML is a rowset provider, OPENXML can be used in Transact-SQL statements in which rowset providers such as a table, view, or the OPENROWSET function can appear.