Native Office Open XML (NOOXML for short) is a native implementation of the Office Open XML (OOXML) ISO/IEC 29500 standard. OOXML is used e.g. in Microsoft Office as the file format denoted by the .docx extension.
Office Open XML is an extremely feature rich markup language who's implementation is very challenging for existing applications.
NOOXML is a native implementation of the Office Open XML standard. This simply means we read the standard and we are implementing it.
Here is what it looks like: