The Free On-line Dictionary of Computing (30 December 2018):
(Or "time quantum", "quantum") The period
of time for which a process is allowed to run uninterrupted in
a pre-emptive multitaskingoperating system.
The scheduler is run once every time slice to choose the
next process to run. If the time slice is too short then the
scheduler will consume too much processing time but if it is
too long then processes may not be able to respond to external
events quickly enough.