Open Document Architecture
The Open Document Architecture (or somtimes refered to as Office Document Architecture) is a standard document file format created by the ITU-T to replace all proprietary document file formats.
ODA is detailed in the standards documents T.411-T.424, which is equivalent to ISO 8613.
ODA defines a compound document format that can contain raw text, raster images and vector graphics. The documents have both logical and layout structures. Logically the text can be partitioned into chapters, footnotes and other subelements akin to HTML and the layout fill a function similar to Cascading Style Sheets in the web world.
In 1985 ESPRIT financed a pilot implementation of the ODA concept, involving, among others, Bull corporation, Olivetti, ICL and Siemens AG.
The binary transport format for an ODA-conformant file is called Open Document Interchange Format and is based on Abstract Syntax Notation 1 (ASN.1).
It would be improper to call the ODA anything but a failure, but it's spirit clearly inlfuenced latter-day document formats such as the mentioned HTML and CSS as well as XML and XSL.