foreground vt.
[Unix; common] To bring a task to the top of one's stack for immediate processing, and hackers
often use it in this sense for non-computer tasks. "If your
presentation is due next week, I guess I'd better foreground
writing up the design document."
Technically, on a time-sharing system, a task executing in
foreground is one able to accept input from and return output to
the user; oppose background.
Nowadays this term is primarily associated with Unix, but it appears first to have been used in
this sense on OS/360. Normally, there is only one foreground task
per terminal (or terminal window); having multiple processes
simultaneously reading the keyboard is a good way to lose.