OpenOffice is a set of open-source programs that make up an office suite. It is cross-platform, available for all the major operating systems. The suite consists of a word-processor, spreadsheet, presentation program, database program, vector graphics editor, and an equation editor. Though OpenOffice uses its own file format, it is able to open and save other formats, including the prominent Microsoft Office formats.
OpenOffice also allows for scripting to let users add in additional functionality. Because of this, the feature set has grown to exceed that of Microsoft's.