n. (also 'wall clock time') 1. 'Real world' time (what the clock on the wall shows), as opposed to the system clock's idea of time.
2. The real running time of a program, as opposed to the
number of clocks required to execute it (on a timesharing
system these will differ, as no one program gets all the
clocks, and on multiprocessor systems with good thread support
one may get more processor clocks than real-time clocks).
