Source : Free On-Line Dictionary of Computing

depth-first search
     
         A graph search {algorithm} which extends the
        current path as far as possible before {backtracking} to the
        last {choice point} and trying the next alternative path.
        Depth-first search may fail to find a solution if it enters a
        cycle in the graph.  This can be avoided if we never extend a
        path to a node which it already contains.
     
        Opposite of {breadth first search}.  See also {iterative
        deepening}.
     
        (1995-04-19)