Source : WordNet®

visualisation
     n : a mental image that is similar to a visual perception [syn:
         {visual image}, {visualization}]

Source : Free On-Line Dictionary of Computing

visualisation
     
         Making a visible presentation of numerical data,
        particularly a graphical one.  This might include anything
        from a simple X-Y graph of one dependent variable against one
        independent variable to a {virtual reality} which allows you
        to fly around the data.
     
        {Gnuplot} is the {Free Software Foundation}'s utility for
        producing various kinds of graphs.
     
        {Usenet} newsgroup: {news:comp.graphics}.
     
        The {Computer Graphics Resource Listing} contains pointers to
        several visualisation tools.
     
        {comp.graphics FAQ
        (ftp://src.doc.ic.ac.uk/usenet/news-info/comp.graphics/)}.
     
        {Electronic Visualization Laboratory, University of Illinois
        at Chicago (http://www.ncsa.uiuc.edu/EVL/docs/Welcome.html)}.
     
        (2002-02-21)