Source : Free On-Line Dictionary of Computing

single sourcing
     
         Using a single original document set to generate
        {dead tree} and on-line {documentation}, and usually also
        on-line help.  In practice, it most often refers to a
        {FrameMaker} file set with {conditional text} which, when the
        conditions are set appropriately, allows you to create
        variants of the original document (e.g., for a product that
        runs on different {Unix} {platforms}) as well as for different
        media -- typically task-oriented on-line help to be accessed
        under {Microsoft Windows} or from a {web browser}, linear
        printed document, and {HTML} delivered via the {WWW} and/or
        {CD-ROM}.