Large document created by Apache OpenOffice (formerly OpenOffice.org), a free, cross-platform productivity application suite; may contain a table of contents, page text, formatting, graphics, spreadsheets, and other document materials; used for storing books or long reports.

Master documents are useful when the file size of a normal documents (.SXW files) becomes too large for the computer to handle. They allow smaller documents to be referenced so they are not loaded into the program. Typically they are only used by advanced users. NOTE: Apache OpenOffice now uses .ODM files for master documents.