Source : Free On-Line Dictionary of Computing

minimax
     
         An {algorithm} for choosing the next move in a two
        player game.  A player moves so as to maximise the minimum
        value of his opponent's possible following moves.  If it is my
        turn to move, I give a value to each legal move I might make.
        If the result of a move is an immediate win for me I give it
        positive infinity and, if it is an immediate win for you,
        negative infinity.  The value to me of any other move is the
        minimum of the values resulting from each of your possible
        replies.
     
        The above algorithm will give every move a value of positive
        or negative infinity since the value of every move will be the
        value of some final winning or losing move.  This can be
        extended if we can supply a {heuristic} {evaluation function}
        which gives values to non-final game states without
        considering all possible following complete sequences.  We can
        then limit the minimax algorithm to look only a certain number
        of moves ahead.  This number is called the "look-ahead" or
        "ply".
     
        See also {alpha/beta pruning}.
     
        [Is "maximin" used?  Is it significantly different?]
     
        (2000-12-07)