Source : Free On-Line Dictionary of Computing

memory leak
     
         An error in a program's {dynamic store}
        allocation logic that causes it to fail to reclaim discarded
        memory, leading to eventual collapse due to running out of
        memory.  Also (especially at {CMU}) called {core leak}.  These
        problems were severe on older machines with small, fixed-size
        address spaces, and special "leak detection" tools were
        commonly written to root them out.
     
        With the advent of {virtual memory}, it is unfortunately
        easier to be sloppy about wasting a bit of memory (although
        when you run out of {virtual memory}, it means you've got a
        *real* leak!).
     
        See {aliasing bug}, {fandango on core}, {smash the stack},
        {precedence lossage}, {overrun screw}, {leaky heap}, {leak}.
     
        [{Jargon File}]
     
        (1995-02-17)