Source : Free On-Line Dictionary of Computing

epsilon squared
     
         A quantity even smaller than {epsilon}, as small in
        comparison to epsilon as epsilon is to something normal;
        completely negligible.  If you buy a supercomputer for a
        million dollars, the cost of the thousand-dollar terminal to
        go with it is {epsilon}, and the cost of the ten-dollar cable
        to connect them is epsilon squared.
     
        Compare {lost in the underflow}, {lost in the noise}.
     
        (1997-09-05)