background

background n.,adj.,vt.  To do a task `in background' is to
   do it whenever {foreground} matters are not claiming your
   undivided attention, and `to background' something means to
   relegate it to a lower priority.  "For now, we'll just print a
   list of nodes and links; I'm working on the graph-printing problem
   in background."  Note that this implies ongoing activity but at a
   reduced level or in spare time, in contrast to mainstream `back
   burner' (which connotes benign neglect until some future resumption
   of activity).  Some people prefer to use the term for processing
   that they have queued up for their unconscious minds (a tack that
   one can often fruitfully take upon encountering an obstacle in
   creative work).  Compare {amp off}, {slopsucker}.

   Technically, a task running in background is detached from the
   terminal where it was started (and often running at a lower
   priority); oppose {foreground}.  Nowadays this term is primarily
   associated with {{UNIX}}, but it appears to have been first used
   in this sense on OS/360.