:wall time: 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 {tick}s required to execute it (on a timesharing
system these always differ, as no one program gets all the
ticks, and on multiprocessor systems with good thread support
one may get more processor time than real time).
-- The AI Hackers Dictionary