Source : Free On-Line Dictionary of Computing

processor time
     
         The amount of time a {process} takes to run, given
        that it has exclusive and uninterrupted use of the {CPU}.
        Note that in a modern computer, this would be very unusual,
        and so the processor time calculation for most processes
        involves adding up all the small amounts of time the CPU
        actually spends on the process.
     
        Some systems break processor time down into {user time} and
        {system time}.
     
        Compare {wall clock time}.
     
        (1998-03-13)